Unicorn here lol.I can imagine that's like searching for a Unicorn. lol
It's fine, as far as running a full sim on a tiny screen with gamepad controls goes.
It's Deck verified for a start, which means Valve have at the very least checked that it all works ok. I have a global 40fps cap on my Deck in the interest of battery life, and on Low-Medium graphics it's rock solid running a 24 car grid of Minis at Brands Indy. Performance wise it feels like there's still some headroom on these settings.
Realistically though, for anything other than a bit of driving fun to pass an hour or two the Deck (or any handheld) is not exactly a natural fit with sim racing!
PS - FWIW, thought I'd give ACC a go too. Surprisingly (with the same caveats as above) ok performance wise, at least on a quick solo practice session!