I'm using Joplin 2.8.8, Sync Version: 3, Profile Version: 41, Keychain Supported: No, Revision: c2a6a13
with Manjaro KDE (currently Plasma 5.24.6) and Android 9 (Joplin 2.8.1, Database v41, FTS enabled: 1). After experiencing some sync troubles with Dropbox I decided to give Joplin Cloud a chance. I created an account, then made sure both devices were in sync.
Next I connected the desktop app to Joplin Cloud and finished syncing before connecting my phone. While expecting a message like "checking... Finished", instead the phone reported Deleting remote items
and Creating remote items
as if Joplin Cloud contained nothing.
The process ran until almost finished, when it halted with Last error: Sync target is locked - aborting API call
and now I'm really not sure what is the best way to reeastablish sync. Will open a ticket at GitHub on this.