Well, AFAIK it's impossible/very damn hard to print on steam OS, and anything that can't be a flatpak or a container/appimage/binary.... Is not going to stay.
If you say "use the deck as main computer", I think for the most part you will be fine, but when you're not you'll be in a world of pain
Just one thing, SteamOS is specially tricky for this as it doesn't support layers.
Bazzite is also immutable but thanks to the layers I got the main things fixed, and as it's based on silverblue there are a lot more resources to check