That would be journalctl, accessible in App Menu as Logs
Or in terminal.
If you have a crash/freeze, immediate run
journalctl -b -1 -p 0..3 --no-pager
In terminal after you boot back up to look at most recent crash logs.
The -1 is Last Boot and the other numbers are criticality priority.
Given your AMDGPU and that it seems to crash under heavy load ( a game, I think you mentioned in the Original Post), you might try preventing Power Management from interferring with a grub parameter: amdgpu.dpm=0
You would be using amdgpu.dpm=0, not nomodeset: