Mostly low/medium settings, drop the resolution to 1024x960, enable FSR in the Deck’s settings, cap the framerate to 45 FPS and it’ll mostly stay there.
I’m usually really sensitive to anything below 60fps but for some reason it feels very smooth and playable this way.
It plays okay ish on low settings in docked mode. I wouldn't try it in handheld. 20-30fps usually. All my 500 hours are not on deck although a healthy portion of them are.
It's fine handheld. Medium-low settings maintains mostly locked 30 fps (frequently in the 40s if unlocked), chokes a bit in some of the DLC areas, but usually fine there too. Might have a harder time trying to be a SL1 parry god but otherwise perfectly playable.
As far as I know there's no difference between handheld and plugged in with the Deck, it doesn't throttle/lower settings to save power automatically like the Switch does.