As I said above, what we need are more apps allowing the use of private data storage. Your own “cloud” (server).

Right. And F-Droid actively encourages exactly that by calling it an "anti-feature" whenever an app connects to a network service but fails to work with the service of your choosing.

I'm literally telling you about the thing that addresses your exact concern, and yet you're nonsensically bitching that I'm somehow the one who doesn't know what I'm talking about? What the fuck is wrong with you?