Type-Safe Pointers in ATS

I have some posts on ATS that might help, some for a slightly older version but the details about linear types, etc remain the same: https://bluishcoder.co.nz/tags/ats/

If you know other languages the documentation is a lot better than it used to be: http://www.ats-lang.org/Documents.html

The approach I took was treating it like an SML variant, then adding the advanced features as I went along.

No.

ATS has all the ergonomics of a burst reactor core, but as far as safe low-level programming is concerned, it has Rust beat.

It would not if would if they would do where their mouth is. But since it's neither memory safe, type safe nor concurrency safe, there is still a need for actually safe languages. But currently the need for fast and half-safe languages and lot of hype trumps everything.