1. Rails has had direct upload since it introduced Active Storage. No one has uploaded files through their servers in a decade

2. What do you mean? Point whatever CDN you want at your origin

3. Maybe

3a. Yes

3b. Metadata or a new table

4. GraphQL is the single worst technology that has ever been adopted. We adopted at my company...twice. Twice we made the same mistake now we're stuck with it for mobile clients. In fact we're stuck on the old Graqphl RB gem that used a DSL instead of classes, which also blocks our Rails upgrade. We've been able to revert everything back to good ole Rest for another part of the app. Be cautious adopting technologies of large companies.