Next is lovely to work with but it has a flaw. It loses client state between pages if you use getServerSideProps. For any app that needs to load some up to date data on every page if the user is hitting it for the first time, but doesn't need to load it if the client already has it, Next doesn't have a solution. You end up using a persist gateway pattern which is a massive amount of work that you shouldn't really need the client to do.

The problem is that that's pretty much every web app. Every time I've used Next I've end up abandoning SSR and building a plain clientside rendered app.