I've built a small project management system (as I was in need of a custom one) with Unpoly as a proof of concept. And, oh boy, it was easy and fast.
I have a previous experience with VueJS and Django REST Framework. It is nice but it's a whole other kind of work. Too many build tools, CIs, State Management hell...
I'll, if I can, keep developing with the new-new stuff (Unpoly and htmx). Probably won't be 100% of the time since it's far for mainstream technologies.