I tried a sync to the microSD card in my Android 9 phone connected via USB, which Windows sees as a drive but MC sees as an Android device, based on the way it handles sync.
I got the same result as you. Playlists didn't have any leading dots, but included a leading forward slash.
/Music/Pendulum/Hold Your Colour/01 - Prelude.flac
The Playlists using the above paths work in my Sony Music App regardless, without having leading dots. But paths such as above are Absolute Paths, not Relative Paths, so I agree the functionality isn't working as intended.
Part of the problem is that before Android 10 forward and backward slashes are recognised. So maybe there isn't one universal "Android Format" that could be used for all versions, past, present, and future. Forward slashes should always work for Android, but who knows, without testing.
An expression format would be problematic, because then a user could specify an expression that didnt' match where MC actually put the files, using the existing settings. It is really just the first part of the path that needs to be adjusted.
Besides all that, I'm still getting errors with re-sync, incorrect file names on re-sync, files already on the device being put In Queue, and "M3U (relative paths)" isn't putting leading dots "./.." in the Playlist paths for Android anyway. It would be nice if all that was fixed as well.
PS: My Audio Path and Playlist Path settings are the same as yours in Handheld Sync Options. So MC is working the same for Android 9 and 10 by the look of it.