Do many people do bash on osx or zsh on Linux, and would this make much of a difference?
https://pkgstats.archlinux.de/compare/packages#packages=bash...
OTOH, it's only 4-7% on Debian (also opt-in):
I'm firmly in the never-zsh camp, but I'd guess so long as one doesn't do something silly like use #!/bin/zsh in shared scripts you can continue to use whatever interactive shell you like
I had a college who was hard core into fish but had to be completely self sufficient because he was the only user in the office. I presume it's the same as being on Linux in a Windows shop or being on Windows in a macOS shop: no one has the day to day experience to have the answers handy