Hi, Steven, thanks for working on this as well!
I'm joining now in this feature, so I'll be PMing you my google email to be added to the alpha channel as well as my ErrorLog.dat.
I'm using the latest app I could get from the Play Store, as well as MB 3.3.7098 with this debug .exe you provided.
BTW, the issues I'm facing is that my GMMP library indicates that it has 30 tracks less than my MB library. Also, MB doesn't seem to be exporting the playcounts, every file has a playcount of 0 on GMMP
Also, here is the debug log from within the app:https://pastebin.com/ZuUpRCvg
(Its on pastebin because my post seemed to exceed 20000 characters)