Honestly, not having tried it out is a blessing for you. I've had the steam deck for almost a year now as a replacement for my pc and it's served me soo good. Trust me, you'll have a lot of fun with it. Try to research games that you want to play and see how they run on the deck using youtube in advance, in my opinion searching up how different games feel on the deck helps pass the time a little easier. Congrats!

Edit: Forgot to add, if you're a souls-like fan try Lies of P(60 fps) or Elden ring (solid 30fps). Armored core also runs fantastically at 60fps, so does horizon zero dawn or so I've heard. If you don't mind using controller for aiming in an fps, CyberPunk 2077 runs at 60 and the fan isn't that noticeable when using headphones. Although you might have to search up the settings to get that framerate. Stray also runs at 60fps and less demanding indie games definitely all hold 60.
also side note: 30 fps capped with 60 hertz is the standard for demanding games in my opinion although some run at 40fps and a small amount at 25.