diff --git a/.github/workflows/sentry_delayed_job_test.yml b/.github/workflows/sentry_delayed_job_test.yml
index b175190ee..e362ca9d3 100644
--- a/.github/workflows/sentry_delayed_job_test.yml
+++ b/.github/workflows/sentry_delayed_job_test.yml
@@ -26,7 +26,9 @@ jobs:
     timeout-minutes: 10
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-delayed_job/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-delayed_job/gemfiles/ruby-${{ matrix.ruby_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       JRUBY_OPTS: "--debug" # for more accurate test coverage
     strategy:
@@ -52,10 +54,17 @@ jobs:
           sudo apt-get update
           sudo apt-get install libsqlite3-dev
 
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
+
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Run specs
diff --git a/.github/workflows/sentry_opentelemetry_test.yml b/.github/workflows/sentry_opentelemetry_test.yml
index e2cfce3c0..e3731112e 100644
--- a/.github/workflows/sentry_opentelemetry_test.yml
+++ b/.github/workflows/sentry_opentelemetry_test.yml
@@ -26,7 +26,9 @@ jobs:
     timeout-minutes: 10
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-opentelemetry/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-opentelemetry/gemfiles/ruby-${{ matrix.ruby_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       OPENTELEMETRY_VERSION: ${{ matrix.opentelemetry_version }}
       JRUBY_OPTS: "--debug" # for more accurate test coverage
@@ -44,10 +46,17 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
+
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Run specs
diff --git a/.github/workflows/sentry_rails_test.yml b/.github/workflows/sentry_rails_test.yml
index 601235f2f..68f26d86a 100644
--- a/.github/workflows/sentry_rails_test.yml
+++ b/.github/workflows/sentry_rails_test.yml
@@ -22,7 +22,9 @@ jobs:
     timeout-minutes: 10
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-rails/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-rails/gemfiles/ruby-${{ matrix.ruby_version }}_rails-${{ matrix.rails_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       RAILS_VERSION: ${{ matrix.rails_version }}
       JRUBY_OPTS: "--debug" # for more accurate test coverage
@@ -80,10 +82,16 @@ jobs:
           for apt_file in `grep -lr microsoft /etc/apt/sources.list.d/`; do sudo rm $apt_file; done
           sudo apt-get update
           sudo apt-get install libsqlite3-dev imagemagick
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Build with Rails ${{ matrix.rails_version }}
diff --git a/.github/workflows/sentry_resque_test.yml b/.github/workflows/sentry_resque_test.yml
index 9b87eb67d..6de695492 100644
--- a/.github/workflows/sentry_resque_test.yml
+++ b/.github/workflows/sentry_resque_test.yml
@@ -36,7 +36,9 @@ jobs:
           --health-retries 5
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-resque/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-resque/gemfiles/ruby-${{ matrix.ruby_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       JRUBY_OPTS: "--debug" # for more accurate test coverage
     strategy:
@@ -52,10 +54,16 @@ jobs:
           - ruby_version: 'jruby-head'
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Run specs without Rails
diff --git a/.github/workflows/sentry_ruby_test.yml b/.github/workflows/sentry_ruby_test.yml
index 614904ed2..4d95d8783 100644
--- a/.github/workflows/sentry_ruby_test.yml
+++ b/.github/workflows/sentry_ruby_test.yml
@@ -32,7 +32,9 @@ jobs:
           --health-retries 5
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-ruby/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-ruby/gemfiles/ruby-${{ matrix.ruby_version }}_rack-${{ matrix.rack_version }}_redis-${{ matrix.redis_rb_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       RACK_VERSION: ${{ matrix.rack_version }}
       REDIS_RB_VERSION: ${{ matrix.redis_rb_version }}
@@ -70,10 +72,17 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
+
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Run specs with Rack ${{ matrix.rack_version }} and redis-rb ${{ matrix.redis_rb_version }}
diff --git a/.github/workflows/sentry_sidekiq_test.yml b/.github/workflows/sentry_sidekiq_test.yml
index 0f3244128..e77dfe0f3 100644
--- a/.github/workflows/sentry_sidekiq_test.yml
+++ b/.github/workflows/sentry_sidekiq_test.yml
@@ -36,7 +36,9 @@ jobs:
           --health-retries 5
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-sidekiq/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-sidekiq/gemfiles/ruby-${{ matrix.ruby_version }}_sidekiq-${{ matrix.sidekiq_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       SIDEKIQ_VERSION: ${{ matrix.sidekiq_version }}
       JRUBY_OPTS: "--debug" # for more accurate test coverage
@@ -69,10 +71,17 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
+
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Run specs with Sidekiq ${{ matrix.sidekiq_version }}
diff --git a/.github/workflows/sentry_yabeda_test.yml b/.github/workflows/sentry_yabeda_test.yml
index 8cdcd88bd..fa2267c56 100644
--- a/.github/workflows/sentry_yabeda_test.yml
+++ b/.github/workflows/sentry_yabeda_test.yml
@@ -26,7 +26,9 @@ jobs:
     timeout-minutes: 10
     env:
       RUBYOPT: ${{ matrix.options.rubyopt }}
-      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-yabeda/Gemfile
+      # Pin via the wrapper gemfile + its sibling .gemfile.lock (BUNDLE_LOCKFILE is unsupported on older bundlers).
+      BUNDLE_GEMFILE: ${{ github.workspace }}/sentry-yabeda/gemfiles/ruby-${{ matrix.ruby_version }}.gemfile
+      BUNDLE_FROZEN: "true"
       BUNDLE_WITHOUT: rubocop
       JRUBY_OPTS: "--debug" # for more accurate test coverage
     strategy:
@@ -43,10 +45,17 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
+      # Wrapper keys the lock to this cell (<cell>.gemfile -> <cell>.gemfile.lock); must exist before setup-ruby.
+      - name: Write wrapper gemfile
+        run: |
+          mkdir -p gemfiles
+          echo 'eval_gemfile "../Gemfile"' > "$BUNDLE_GEMFILE"
+
       - name: Set up Ruby ${{ matrix.ruby_version }}
         uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
+          bundler: latest
           bundler-cache: true
 
       - name: Run specs