timo Hi Timo, the first 3 steps are correct, except that I think I accepted the second request for full access.
Next, I logged into OneDrive - I think I saw both full access and apps folder permission granted to Diarium, which I then cancelled, and also cancelled sync in Diarium.
A few days later, as an experiment, I activated sync in Diarium, again choosing Onedrive, but this time saw only one permission request ( app folder) . Sync appears to be working as expected - will be going through this process with a few other devices over the next week so will let you know if anything unusual happens. Thanks for following up.