I don't love the idea of implementing common app state logic via attributes. It probably works a lot better than I'm assuming, but it feels hacky to me. Like it can't solve every problem you'd actually encounter when making a complex app, so eventually you'll need to fall back to using javascript, and possibly a framework or three...on top of htmx. But it does seem like this would be fun to play around with using PHP…
https://htmx.org/essays/hateoas/
it really tries to focus on extending HTML & the original model of the web, rather than replacing it w/something else
good for some stuff, not good for other stuff
i like using events when I need to tie things together with some scripting: