Out of the box on steam deck OLED with recommended settings, DRDR plays at sub 30fps, but it can be played at 30-40fps with these settings.

Don't use the game's FSR settings, they make the game look terrible. Steam's FSR works much better if you want to reduce the resolution to 960x540, but in my testing, it doesn't boot the fps by much.

My Settings:

Anything unlisted here shuld be set to Off.

Screen Resolution: 1280x720

Refresh rate: 90Hz

Fram rate: Variable

Display mode: Window

Texture quality: High 1GB

Texture filter: High ANISOx2

Shadow quality: Medium

Anti-aliasing: TSAA

Image quality: 100%

Mesh quality: Medium

Screen space reflections: On

Volumetric lighting: Medium

Ambient Occlusion: SSAO

Subsurface scatterig: On

Shadow cache: On

Bloom: On

Lens flare: Ong

Number of characters on screen: Many

Persitent corpses: Many

Motion blur: On

Depth of field: On

Color space: Rec202 (unchangeable)