have you seen https://vite-plugin-ssr.com/ ? i've only browsed their docs, but AFAICT the pitch is that it's a more DIY approach to a framework, where you keep a lot of control over how things are wired together.
Love this. I've always thought we needed "metaframeworks" for JS. The ground shifts too quickly on things like state management, routing, styling, etc. to be locked into a single library.