Frame rate and optimization issues currently leave CS2 anything but playable on Steam Deck, but it appears that Valve is working quickly to fix things.
I tried CS2 on my Deck after the update. I only tried against bots on Italy but found that given the hardware, it ran surprisingly OK. 40 FPS with default settings. Obviously the controls are not so great. I've read somewhere later that resetting Steam Input for this game to defaults is required but didn't know that at the time.
Btw I played with the Deck on a stand and my left hand on the controller part while my right hand held a Bluetooth mouse.
Is that… comfortable? That sounds like a really awkward way to play.
It was kinda OK. It actually had the benefit of analog movement as compared to WASD. Biggest downside was the small screen.
Any reason you didn’t do all in on the controller or keyboard+mouse?
The game did not seem to work with controller only and forced me to use the trackpads and I cannot play FPS games with just a controller anyway. As for why no keyboard, the answer is simple: I was too lazy to get up and get my BT keyboard and my USB C dock (all my Deck accessories are stored in a dedicated bag).