You're not the first, nor do I expect you'll be the last, to reinvent the build scripting wheel. Things like this are why languages like Zig have decided that the build script language should just be the same as the actual programming language.
Doing a cross platform subset is an even nice combo of learn something and keep my build scripts bash-y.
Like I said I really don't want to make these scripts more verbose than bash and any other language would mean doing that.