I had actually assumed they stopped supporting it so I kept mine unplugged for a year or two. Turned it on the other day on a whim and was surprised by having to wait on a new update.
You can use any controller with a steam deck though. I use our ps5 controllers to play cult of the lamb with my husband and I have a wired Xbox controller I've used as well. Both work flawlessly.
It quite often didn't recognize the HDMI output so I'd have to try all kinds of things like rebooting and unplugging/replugging until it would finally output to my screen. Also had some trouble getting it to start charging a few times.
For everyone having this issue, try plugging in the deck to dock with only the HDMI plugged in and no power cable. This worked for my TCL TV. Once the screen screen shows on the TV, you can plug the power cable back in and it should still work
Sure. Or you could use Bazzite. But I want something I don't have to faff around with, like the Steam Deck. Plug it in and start gaming. That's the selling point. If Valve can achieve that, make it perform well and be affordable, they have yet another goldmine.