How to change render camera and resolution and camera distance

[LunaBright]

I noticed that the Gaussian render had set the camera id, so I tried to render it in launch_nodes.py. I tried to change the camera id in this file but the render view didn't change, so I didn't know how to change it.
At the same time, the resolution of the rendering is not high enough. Which parameter in which file is the real control parameter of the final rendering resolution?
My rendering shows the camera far away from the robot, but the actual camera is much closer. Is this because Gauss didn't do the same transformation and scaling for the camera? How did you solve this problem?

[LunaBright]

My real problem, perhaps, is that my rendered image of the camera is so far away from the robot arm that it doesn't match the actual camera distance or position. What could be the reason?