Compatibility Report

• Name of the game with compatibility issues: Metal Gear Solid V: The Phantom Pain
• Steam AppID of the game: 287700

System Information

Steam Deck

I confirm:

• [X] that I haven't found an existing compatibility report for this game.
• [X] that I have checked whether there are updates for my system available.

Symptoms

When you launch MGSV, "Failed to load SteamAPI" error shows up, and then the game closes.

Reproduction

Use any Proton version later than 7.0-6 (including 10, 11 experimental, and ge custom)