I recently received a Steam Deck and I love it!
I also planning to use it for development. On my PC I get used to Fish shell and usually use it instead of Bash. I can install it on Steam Deck and set it to the default shell, but after a system update it will be wiped. I can create a script and run it after each update, will I be able to login if my user points to /usr/bin/fish that doesn’t exist in the system?..
Dont own a steam deck, but at a guess you might be able to add the terminal lines to change shells to you bashrc, should load it in on first start and then fish will be default from then on.