Hello @biabiabia66
To answer your questions:
Yes, there are cache files generated:
https://dev.epicgames.com/community/learning/knowledge-base/KKn1/capturing-reality-cache-temp-folder
https://dev.epicgames.com/community/learning/knowledge-base/jwOO/capturing-reality-files-stored-by-realitycapture#:~:text=the%20main%20folder%3A-,Cache%20files/temp%20data%20files,-RealityCapture%20also%20uses
Which weight setting do you mean?
The cache files are not readable, they are there for the smooth operation of the project, also detected features can be stored there.
Regarding project folder you can find more info here.
They are created for the project, not for your usage.
To get PINHOLE cameras you need to use the undistorted images and set the camera’s Prior lens distortion as Prior: Fixed, Camera model: No lens distortion for the selected images after import (see Camera Models — COLMAP 3.12.0.dev0 documentation).