I've been meaning to try it, but also know its going to suck me in hard if it works well, so have been waiting for the right time.
Playing on a PC vs the Deck (or other similar portable) is like the difference between being an addict and the dealer using their own product.
I haven't tried it but I've heard that it is completely playable, although I'm sure not as convenient as using a mouse and keyboard.
While I wouldn't play RTS games on it, the pads combined with the fantastic steam input that lets you rebind any button to any keypress (or a macro of presses) makes it so you can be fairly sure you can play most mouse keyboard+mouse games on it.
Now with the controller support added to the PC version of the game from the Switch release.