I recommend checking out Alpine.js which looks and feel like Vue 1. They don't have any ambition to be anything more than that.
I like the idea of it but for what I work on the CSP non-compliance is a deal breaker (their CSP compatible build is not ready and you lose most of the alpine benefits).
https://alpinejs.dev/advanced/csp
I think that Stimulus JS offers many of the same benefits and provides a nice abstraction for making one 'element' contain multiple behaviours.
https://docs.servicestack.net/api-explorer
Originally we started out with VanillaJS & hand-rolled MVC pattern however the productivity slowed as the App was getting larger, switching to petite-vue was a major productivity boost giving us a productive reactive UI, ability to componentize our App into modular components & resulted in the fastest UI we've seen in a client UI.