SSR because I want to have offline support
SSR isn’t a prerequisite for offline support.
Offline support is accomplished via Service Workers. Now in the simplest case a Service Worker can cache responses which could be rendered pages but client side JavaScript can be cached as well. With an SPA you would tend to also use IndexedDB (with Promises) to stash some data for offline use.
Have a look at
Progressive Web Apps: Going Offline | Google for Developers
Gemini-powered solutions | Google for Developers
https://youtu.be/psB_Pjwhbxo?list=PLNYkxOF6rcIB2xHBZ7opgc2Mv009X87Hh
