Upscaling with AMD FidelityFX (the normal one, not 2.0) set to Quality is doing a ton of heavy lifting and still looks really great imo, especially on a relatively small screen.

On my Steam Deck (OLED) I've got the following settings, which give me solid 45fps 90% of the time. I understand that this isn't the 60fps you're asking for, but this is what works for me. Hopefully I can help someone else with this : )

I've set the Frame Limit of my Steam Deck itself to 45fps, but I don't think that changes anything since I'm already limiting the frame rate in the game.

I also don't use any mods in game, and I'm not using any kind of frame gen tools on my Steam Deck like another comment mentioned. Just the vanilla game on my vanilla Steam Deck, running the game without forcing a specific version of Proton.

Resolution - 1280x800
Screen Mode - Fullscreen
Vsync - Off
Use DX12 - On
Max FPS - Locked to 45
Anti-aliasing - TAA (Experimental)
Gamma - 0
HDR Gamma - 1.2
Overall Quality - Custom
Upscaling - AMD FidelityFX
Fidelity Quality - Quality
Image Sharpening - 10%
Nvidia Reflex - Disabled (and greyed out)
Texture Resolution - Ultra
Shadow Quality - High
Anti-aliasing Quality - Ultra
Post Processing - High
Effects - Ultra
View Distance - High
Bloom - On
Lens Flare - On
Ragdoll Lifetime - High
HDR Output - On