Hi! Here are my answers 🙂
1. No. You can do it, but you would have to call the Office365 API. Not a trivial task
2. You have to do that. No matter which backend you use, it is up to the developer (for now) to implement that yourself
3. It does not
4. Using Excel as a backend is not a good idea. For a proper web app, you need a proper backend (database, authentication, authorization, business logic etc...). Excel does not provide any of that. I recommend that you take a look at real backends like Xano or Supabase