I ran into a tiny problem while playing it on Linux Mint. The game would freeze after a certain ammount of time, but increasing the max_map_count to that of the steamdeck fixed it. (Mint has a really low default one)
Now its running without problems.
Have you tried to increase/check the max_map_count ? That fixed it for me.
https://www.gamingonlinux.com/2024/01/the-finals-freezing-on-linux-heres-ways-you-can-fix-it/