[skydhash]

And if you’re not building a very interactive desktop app, you have no need for an SPA.

[DeathArrow]

How would something like Facebook, Instagram, Netflix work and look if they weren't Spas?

[skydhash]

There's nothing inherent to those sites that warrant SPAs. Things that do warrant SPA are full blown apps like Gmail, Figma, Google Maps,... or if you're building a desktop-like dashboard like Synology NAS's.