I use OneDrive which had been syncing flawlessly until the mandatory switch which Samsung forced upon us because Samsung Gallery Sync will cease this year.
That's fine and I'm happy to continue with OneDrive, however the switch has caused gallery to stop syncing, meaning that it has to be reenabled manually through settings>accounts and backup>manage accounts>OneDrive>sync account>media storage button.
I have also checked permissions and other settings for OneDrive and Gallery, but this media storage setting insists on resetting itself, regardless of activity.
I've sent a bug report to Samsung and am waiting to see if they reply.