From reading this forum and GitHub it appears that with Joplin Desktop v3.2.3 OneDrive sync was "deprecated". What this actually meant was that OneDrive was removed as a sync option from the Sync Wizard. OneDrive sync would still work and was still an option under Tools > Options > Synchronisation.
However a later GitHub post stated that further consideration meant that this decision was being reversed and OneDrive would be reinstated as a Sync Wizard option. It looks like this change was in v3.2.4 (also a pre-release version).