Update on the JS front-end thingy:
I think the rails folks did something fun: hotwire works pretty well in giving the impression of an SPA but with server-side rendering
Since I'm using a clojure stack I had to write some code just so I had to render less than needed when a turbo-frame request shows up, but it wasn't strictly necessary. Most interesting aspect of it is that I was able to develop like an OG web app (productivity up, complexity down) and then plug it later in an afternoon
the "glue-code" was to be aware of the turbo-frame header on the request. If present, then we only render the frame needed for the request and ignore the rest of the html surrounding it. Since I'm stitching together a number of libraries on Clojure, this one was on me... but I saw some libraries for Python environments that do the same