Spoiler: I didn’t try to fix the bug, i was going the lazy way and i just hoped
it would cure itself, because it was maybe just a buggy flatpak update and i think that’s what it is now actually 
A little overview, after the latest release update (09/02/24) i no longer experienced the in game system freezes. But it changed back to my old problem, with the system freeze after the game was closed for few minutes.
I also found out that it had something to do with system (probably GPU) idling, because i could delay the freeze when i start watching a video right after my gaming session and it freezed just after closing the video player.
Anyways, around 10 days ago i had another Flatpak update, i think all my packages was updated excluded the nvidia flatpak driver, i was firstly disappointed.
$ flatpak list
Name Application ID Version Branch Installation
BAR Team info.beyondallreason.bar 1.2988.0.0 stable system
Freedesktop Platform org.freedesktop.Platform 23.08 system
Mesa org.freedesktop.Platform.GL.default 24.2.1 23.08 system
Mesa (Extra) org.freedesktop.Platform.GL.default 24.2.1 23.08-extra system
nvidia-550-107-02 org.freedesktop.Platform.GL.nvidia-550-107-02 1.4 system
openh264 org.freedesktop.Platform.openh264 2.1.0 2.2.0 system
But since this last update, i have not a single system crash for around 7-10 days and i openend/closed the game several times a day, only to force if the system freeze will show up again, but no way… full stable again 
On one side, im happy that the problem is gone now… but i find this strange that a flatpak update from a game could have this strong impact on a stable system… 
Just a guess from my side, it maybe could be related to the Manjaro/nvidia driver delay, since our distro still stays on v550 
Thanks again for the support guys, i hope that the problem won’t show up again. Since there is no solution the Topic can be closed.