What version of MC are you using Jeff?
Basically, PLA files are/were used on Android by lots of Apps, but mostly those Apps can read m3u Playlist files and create their own PLA files, if required. PLA files are weird, particularly on Android. They don't have content, but store the Playlist data in metadata for the file. Creation and syncing of PLA Playlist files was removed from MC back in MC24 I think.
Googling PLA will find lots of discussions where people are trying to work out what they are, and how to use them. Avoid the grief. Use m3u Playlist files in Handheld Sync. They work with my Sony Xperia on Android 9 just fine. Android 10 may have its own issues, but I doubt it has reverted to insisting on using PLA files.
Also, you shouldn't be syncing Playlist files directly, which sort of sounds like what you are doing. Tell MC which Playlists to sync using the Handheld Sync functionality, and it will sync the files included in those Playlists, and create new Playlist files on the handheld device. Have a read of the Wiki articles on Handheld Sync if in doubt.
PS: I have seen MC fail to create all Playlist files on a Handheld during a sync, if a lot of Playlists were selected. I haven't seen that for a while, but I haven't synced lots of Playlists for a while either. Using just a few.