Hi Im having a similar issue:
Diarium version: Win 3.2.4.0, Android 3.2.3
OS + version: Win 10 (Bought from Microsoft Store, Android 16
Device model: Fold 7.
Both device has cloud sync to the same google account, both has tick mark.
Phone i entererd say example 20 emtries, only 5 showed up on Window version. The fact it has some entires says that the sync is correct, its just not syncing all the entries.
Please help.