My only hesitation here is that this change can break some cross-document references. For example, someone might have rendered a paper that points to documentation at https://docs.racket-lang.org/ on the theory that tag links are stable. I don't know how big of a problem that might be, though. Any thoughts?

I've sometimes had to write things like @tech{syntax class}es to get links to work, so I can certainly appreciate the improvement.

It's possible. I don't know of a good fix for that problem. But I don't think "we can never change anything about how tag links are created" is an acceptable stalemate. Is there a way we can check that this at least doesn't break any documentation links in existing packages?

We could just generate both tags in the HTML.