Valve have released a new Proton Hotfix update which solves issues with both The Finals and Grand Theft Auto V Enhanced (offline play) on Linux / Steam Deck.
Read the full article here: https://www.gamingonlinux.com/2025/03/proton-hotfix-updated-to-fix-the-finals-and-grand-theft-auto-v-enhanced-offline-on-steam-deck-linux/