https://htmx.org/essays/when-to-use-hypermedia/ addresses your first question. The tl;dr is "probably not" as htmx is not really designed to handle complex browser-based UIs, but I have seen people in this thread and elsewhere discuss more complex use cases, so YMMV.
https://htmx.org/essays/a-real-world-react-to-htmx-port/ is about porting a serious production Django application from React to htmx.
If you hate SPAs and are chafing against Vue for building your app, it's probably worth considering if your app absolutely needs to be a JS/frontend-heavy product, or if it would be viable using a more traditional HTML+AJAX design.