How do you read an "alien" file from Download under SDK 30?

[Johannes_Ai2]

You cannot access non-media files on devices with Android 11+ that are not created by the app itself since targetSdk = 30. You must use the Storage Access Framework (SAF) for this.

Εrror 2101:Τhe file/filename.txt coult not be found

You can no longer access non-media files (.txt) in the root dir of the external storage or an arbitrary folder on Android 11+. In order to be able to access such files, They must be in one of the Shared folders (/Documents or /Download) and must have been created by the app itself. They must be in the ASD. (In this case, it doesn't matter if the file was created by the app or manually copied to the ASD, using a file manager.) Or use the Storage Access Framework (SAF). (But in this …