You can use zsh as the default shell and still write your scripts for bash. Actually, it’s an advice I saw more than a couple of times. Otherwise you need to translate the bash-isms when you get bits of code from random places on the Internet.
Just put the right shebang (or ask Claude to do it). What’s the problem?
But maybe that's because I'm the sucker, and since PowerShell is more verbose it costs me more tokens than the terseness of Unix shells. Oh well.