Also it’s not the best for creating OS processes and/or interacting with stdio.

Yeah, this miffs me too (a half second startup time, locally), which has got me even looking at languages like Idris that can compile down to C and then thus to an instant-start app.

You can definitely get startup mich faster than half a second if you tweak the start script and maybe start only one scheduler, etc.

I don't think it will be great without heroics, but a little work and I think you can get it down to < 100ms.

It needs a Babashka equivalent.