> Of the four choices, Zig today is already simplest to learn,

Yes, with almost complete lack of documentation and learning materials it is definitely the easiest language to learn.

For reference, here's where Zig's documentation lives:

https://ziglang.org/learn/

I remember when learning Zig, the documentation for the language itself was extensive, complete, and easily greppable due to being all on one page.

The standard library was a lot less intuitive, but I suspect that has more to do with the amount of churn it's still going through.

The build system also needs more extensive documentation in the same way that the stdlib does, but it has a guide that got me reasonably far with what came out of the box.