Sync target. Database instead of files

From my understanding it is not easy/impossible to reliably sync a database via OneDrive, Dropbox, Nextcloud etc. These services are build for file-sharing not for a database. It can lead to sync errors and inconsistent data. I dont understand the technical details but there is a bunch of information if you google it, two examples.

Here is a little speed comparison of Joplin Server vs. Nextcloud: