Earlier quoted context omitted.
Doesn't HTMX work via HATEOAS so would require a full RESTful backend?
You can just respond back anything and it'll work. You can just respond a flat non-hypermedia JSON and have some JavaScript listen to the event and process it with whatever semantics you want (although it'd be weird for you to do that, but I just tried it and yeah it works). I still don't understand what they mean when they say "HTMX is HATEOAS": it's not parsing the response to decide things based on relations, it's…
REST was ok for the read-side of things, but for writing I find RPC/commands to be better than PUT/PATCH. Combine that with the lack of framework for HATEOAS made full REST APIs cumbersome at the time, though things may be different now.