There's currently somewhere around 92,000 games on Steam and so it's going to take a long time for Valve to check them all on Steam Deck but here's some recent picks.
The true number of playable games is of course much higher, but this is still an impressive milestone.
For comparison: the Nintendo Switch has roughly 4500 games available for it, the PS5 has about 500 games (+ 3500 PS4 games), and the Xbox Series X/S have 400 (+ 3000 Xbox One games).
You have my sympathy. If I could change two things about Valve's handling of the deck, I would make it available in more regions and make SteamOS available for other handheld PCs.
I've heard that while it's not exactly SteamOS... ChimeraOS gives a very similar experience, should you own one of those Windows handhelds and don't want to use Windows primarily on it.
I think that's a great option for end users, but I'd really like to see it as an officially supported OS for these devices when purchased.
If nothing else, the companies could offer a version of the device without an included license for a discount, I think saving 50+ dollars up front and getting a better user experience would be appealing to a lot of people.
I got one of amazon.com.au in June. The price was pretty much the same as the direct conversion from USD, and it got delivered the next day. Obv a 3rd party seller but have been super happy with the purchase.