How are you determining that RAM overflows? Can you explain “blank screen and working control” in a little more detail? Not trying to be difficult, just more detail will help us help you. Is the “oom killer” in question systemd-oomd or do you mean you’ve configured the kernel OOM killer in some specific way?
See Viewing logs in Fedora :: Fedora Docs for a quick guide to seeing system logs.
In the systemd-oomd case:
$ journalctl -n100 -u systemd-oomd
will give you the last 100 log messages from systemd-oomd. (-n100 could be replaced with -b or some other thing, or just left off to get the default, which I think is 1000 lines. And -u filters by the “systemd unit”, which is generally the service name.)
For the kernel OOM killer:
$ journalctl -k -g OOM
where -k means look for kernel messages and -g OOM “greps” for the string OOM and shows you only the lines that match.
But are you sure this isn’t a graphics driver problem? GTA 5 is Grand Theft Auto V, right? Are you running that through Steam / Proton? That can be kind of intense and expose driver bugs, cross-platform quirks, or even hardware problems.