I'm very curious about the Steam Deck (especially because it runs Linux), but it's just too big for my taste. There are other companies making very similar devices (which are often more powerful too) that are smaller (like Ayaneo [1]), but so far they are all running on Windows. (Seems like they are making their own Linux-based OS though.)
If you have a friend with a Steam Deck, I highly recommend just giving it a shot.
I thought my Switch was too big and even got a Switch Lite, then when I got a Steam Deck (“worst case I’ll just dock it”) it was so much nicer. The grips cancel some of the size out, and it’s more comfortable (to me) than my (full size) Switch, despite the weight differences.
I wish there was a Switch Lite-sized one capable enough, though. But so far it’s all either: throttle, low battery life, no support, or extremely expensive (e.g.: the $1000+ ones).
I have the body of a large 13 year old, and I'm so glad I got a switch instead. What Valve has accomplished is amazing, but my friend has a Steam Deck and it's just too heavy for me. 5 minutes in and I could feel the strain.
The switch controllers, when decoupled, fit my hands perfectly without weighing anything. It works much better for me and my puny wrists.
[1]: https://www.ayaneo.com