Most stuff ends up beeing Client Components - since what else do you really need react for?
There are good parts like server actions, however they are plagued with very strange limitations making them not so useful.
If you want to statically generate websites and want to use React, NextJS can be a good choice, however for complex web applications I find that it's not ambitious enough to justify even the extra compile time that I get from its tooling compared to Vite.
Why would you optimise for SEO on a webapp? What's the use-case there?
If you're not writing a webapp, then any server side rendering would do and client side components aren't needed anyway.
I'm not sure if I would do it again though, but we'll cross that bridge when we get to it.