I prefer getting comfortable with bash, because it’s everywhere and I need it for work anyway (no fancy shells in remote VMs). But you can customize bash a lot to give more colored feedback or even customize the shortcuts with readline. Another one is pwsh (powershell) because it’s by default in Windows machines that (sadly) I sometimes have to use as VMs too. But you can also install it in linux since it’s now open source.
But if I wanted to experiment personally I’d go for xonsh, it’s a python-based one. So you have all the tools and power of python with terminal convenience.
powershell, in concept, is pretty powerful since it’s integrated with C# and allows dealing with complex data structures as objects too, similar to nushell (though it does not “pretty-print” everything the way nushell does, at least by default).
But in practice, since I don’t use it as much I never really get used to it and I’m constantly checking how to do things… I’m too used to posix tools and I often end up bringing over a portable subset of msys2, cygwin or similar whenever possible, just so I can use grep, sed, sort, uniq, curl, etc in Windows ^^U …however, for scripts where you have to deal with structured data it’s superior since it has builtin methods for that.