There's plenty of non-Vercel attempts at this and it's kind of table stakes for frameworks hoping to get popular. There is a push for server-first/MPA app development where SSR is assumed to be the baseline. Remix [1], Qwik [2], and Marko [3] are in that camp. I'm not sure about Remix but the other two have a goal of authoring the entire app components but only sending the JS needed for the parts that can change on the client.

[1] https://remix.run/ [2] https://github.com/BuilderIO/qwik [3] https://markojs.com/