for the other stuff, the growing browser stdlib has basically replaced most of jquery's usecases. so (in the most non condescending or negative way possible) htmx occupies a very awkward sliver between "The Platform" and Frameworkland and after giving it some time I have yet to see the benefit from keeping any of it in my head
At all.
Every time web sites reimplement basic browser behavior, which they invariably do these days, they get worse, often significantly, because they never get it right.
I think you are overestimating how much 'UI standards' have gone up over time, actually. Nobody except for a small 'extremely online' set of people and control-freak designers care about all those complex UI/UX requirements. Users certainly don't care. They want fast-loading, responsive pages that get out of the way and don't drain their batteries or clog up their connection.
The other thing here is that approximately no one can actually tackle the complexity introduced by SPA frameworks and 'UI standards', and it's far more likely that they bungle it up and make giant, wasteful, UX pitfall-ridden apps. With server rendered pages, plain old HTML, and progressive enhancement, we at least have a better chance of producing something usable.
And then you end up with modern SSR frameworks that do the bookkeeping for you.
we can basically get the benefits of spa without having to learn js / use minimal js using htmx in some sense
https://github.com/donseba/go-htmx check this out
You can replace elements outside of your direct tree if you want. The simplest case you replace the whole page and pick what elements you actually want to change.
You're thinking about HTMX wrong. It's for progressive enhancement, the default is a full page reload and then you progressively enhance parts of the HTML. You should be using the same code paths and template to generate the islands of interactivity as you do for the whole page. You can then optionally send less HTML by just sending the parts that you expect to have actually changed, your "islands".