Maybe Vue and Svelte are different. But something like react is "just a library", right? So they must be greenspunning their own framework as well, by their own

Maybe Vue and Svelte are different. But something like react is "just a library", right? So they must be greenspunning their own framework as well, by their own admission. So then ask yourself the question - which underlying tech of your in house framework is going to be more stable, supported, have better tooling, and be easier to reason about. I'd pick the DOM every time.