if the only problem with PowerShell is that it feels clunky and annoying, why not try to extend/improve it (like Kotlin over Java)? Why start a new project that will maybe catch up in X years?
Plus the fact that PowerShell is .NET-based and not the most snappy shell out there either.
Plus the fact that extending something requires investing a lot of work just understanding how things tie together, and then avoiding messing up all the hacks and idiosyncrasies added along the way instead of having a clean slate to build on.