I don't know about the kind of web apps you've been building, but most of the ones I've built over the last 10-15 years have had too much interactivity to be done with simpler server side rendering.
Everything from MPAs, to SPAs, to animation heavy websites that could only dream on being tailwind. Progressive enhancement doesn't mean giving up on frontend validation, dynamic functionality, and juice. I'm curious what problems you haven't been able to solve without converting whole applications to JSX.
Just because problems are possible to solve in a hybrid approach doesn’t make the hybrid approach the ideal solution for complicated UI.
My idea of a complicated UI challenge is not updating DOM in two trees. I have found React to be inadequate for the hardest UI challenges that I've been presented with. Things like DOM manipulation for interactive animations should not be handled by React state updates.
I think the SPA and the no-JS SSR people get it wrong by making it so black and white. By choosing to use something like React, you've made everything only SPA. With SSR, you can at least choose to progressively enhance the interactions. Look at amazon.com. They have plenty of full page reloads, yet their site also has tons of interactivity. Just make sure that the thing you require a full page reload for happens at a natural transition where it isn't interrupting the user's experience.
That's the exact opposite of my experience. Completely boring biz software that was, in essence, collections of forms. Didn't need the additional development burden of an extra JavaScript codebase, but that's what's in vogue, so ¯\_(ツ)_/¯
If so, it probably didn't need any development burden and could be done using a no-code or low-code solution.
No|Low code solutions often generates hard to maintain code so you essentially find yourself locked to the platform and version you started with.
Most low code/no code solutions bring back memories of Access and Excel based solutions.