deck game-specific settings:

• Compatibility: proton experimental
• refresh rate 40hz
• allow tearing
• half-rate shading off

in-game settings:

• master quality: very low
• fullscreen
• 40fps limit

For some graphically-intensive builds or that one map in the swampy area that i cannot for the life of me maintain 40fps, i turn the resolution down in-game (but still fullscreen) and use the deck's FSR at max sharpness, though this does make text a little hard to read, so i try to avoid it. I can generally get away with tdp limit of 10-12W too.