I see a lot of people who read Fielding's thesis and found it interesting.

I did not find it interesting. I found it excessively theoretical and proscriptive. It led to a lot of people arguing pedantically over things that just weren't important.

I just want to exchange JSON-structured messages over HTTP, using the least amount of HTTP required to implement request and response. I'm also OK with protocol buffers over grpc, or really any decent serialization technology over any well-implemented transport. Sometimes it's CRUD, sometimes it's inference, sometimes it's direct actions on a server.

Hmm. I shoudl write a thesis. JSMOHTTP (pronounced "jizmo-huttup")