All code, across all paradigms, frontend, backend, low level, high level, whatever; all code becomes really messy when you have complex state management.
The solution in each of these cases is the same, though. To simplify the state.
In general, I think a lot of the pain in web development comes from attempting to have shared mutable state between backend and frontend. Shared mutable states are almost always messy. You can get around that by pushing it all to the frontend, or pushing it all to the backend. It's when it's straddling both you're in for a headache.
I agree - but you can't simplify when your tools complicate - in the sense that they intertwine different concerns. As soon as you're not dealing with trivial apps "pushing it all to backend" isn't really an option if you want good user experience - and then you'll have to have logic on frontend as well. And that's where the pain comes.
The solution in each of these cases is the same, though. To simplify the state.
In general, I think a lot of the pain in web development comes from attempting to have shared mutable state between backend and frontend. Shared mutable states are almost always messy. You can get around that by pushing it all to the frontend, or pushing it all to the backend. It's when it's straddling both you're in for a headache.