Try connecting to a WebDAV server on File. It's possible but it's shitty. And try using Syncthing on iOS to keep your files synced across devices without having them uploaded to servers you don't control.
Also, on Android, you can choose any file explorer. You're stuck with Files and it sucks (but it looks nice).
Also, on Android, you can choose any file explorer. You're stuck with Files and it sucks (but it looks nice).