Why is it the default for you? You are worrying about hydration complexity and all that when you introduce it, so it better have some benefits.

My default is a small page that client then fetches any additional data it needs. If its long load time skeleton UI it. I also have not seen the SEO benefits at all.

So again _why would I_ unless I needed to do stuff on the server to make the client bundle, which I don't.

A lot of these YC companies doing this could literally just be using a fetch because their backend is dead simple REST.