I switched to fish a few years back after a couple decades of using bash. It took about 10 minutes to make that permanent everywhere – because so much is built-in and the defaults are good, there was no need to spend time on more than the package install plus chsh.

For scripting, I’d already set a personal policy that anything complicated use Python. For me there’s a fairly big difference between interactive shell sessions and scripts which solidly shifts the balance to a full language with a rich standard library and robust error handling. My scripts were edited using shfmt and shellcheck interactively anyway, so switching to Python wasn’t an increase in terms of tool support and the richer language means that I’m writing less code to get more functionality and especially error handling.