Can I sync local file to an android Document Provider?

[arthurcaccavo]

Some apps are registered on android as a Document Providers (i.e proton and google drive) as so they are accessible as "external storage" via the DocumentsUI native app.

As proton connection is still experimental (I'm having issues connecting, specially with the need to provide OTP) I would like to know if it's possible to sync two folders, being one a local folder and the other one a external document provider (proton) using SAF as to not need to inform credentials