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