You don't need maxSdkVersion, You need to request the permission but it won't work with targetSdkVersion greater than 28 so set it to 28 for your own use if the app is nit going in the Play Store.
Look at this example. Although intended to show the use of MANAGE_EXTERNAL_STORAGE it also has the code for getting WRITE_EXTERNAL_STORAGE permission, which also gives you read permission,
Google seems intent on dumbing down Android to the point of uselessnes to me. I think of my devices as little computers and I want a proper file system on them, not the limited tortuous things that Google offers and that I don't understand, ContentChooser, FileProvider, ... o_O I'm getting old...