My Steam library basically only consists of Witcher 3 and Spiritfarer. I also was gifted a Humble Bundle game for Batman Arkham Knight.
I’m debating on getting Elden Ring and Cyberpunk (both without DLC).
Marvel’s Spider-Man and FF7 Interograde also look like a good value right now for 40 bucks total.
While the Deck is capable of running some big AAA games, I personally find that it shines in the low-power, “chill” games that you can play for a while, put down, and come back to when you’ve got some more time.
I’m a big fan of RPGs, so my #1 recommendation is Sea of Stars. Dragon Quest: Builders is also good, along with it’s sequel, which is arguably better.
A good multiplayer game with endless hordes of monsters vs. your magic is The Spell Brigade.
You may not know this, but the Deck can also be plugged into a TV or monitor, and with the help of a USB-C hub, can support a keyboard and mouse too! If you go that route, then I can’t recommend Dyson Sphere Program enough. Ooh! and Timberborn! It’s both adorable and beautifully designed.
If you’re more of a 3rd-person shooter type, Mass Effect: Legendary Edition is fan-fucking-tastic (my favourite series of all time) and it’s currently on sale for £5. There are 3 games in the series, and make sure you start with the first one! You don’t regret it.
Finally, note that you’re not bound to the Steam store if you don’t want to be. If you install the Heroic Launcher for example, you can get DRM-Free games from GOG for example. Sometimes you’ll find that games are available on both platforms, but cheaper on one of the other, and GOG games don’t come with controls on how many people can be playing it at the same time.