timo for example, when I started using apps like Procreate, VSCO and Adobe Acrobat, those apps automatically created their own folders in the On My iPad section of my file manager. I am moving these folders that apps automatically create to a folder on my iCloud I named "All Apps". On my macbook, when I started using apps like Calibre and Obsidian, they asked me to specify a vault or storage location. I created Calibre and Obsidian folders in my All Apps folder and I selected those when Calibre and Obsidian asked me.
When I started using Diarium, I used Google Drive and not iCloud for my Cloud Sync and Diarium automatically created files like "v4_Media", "v4_database", and "v4_mediaindex" which I put in a Diarium folder I created in Google Drive. Now, I decided to put these kinds of files and folders the apps are generating in one place in my iCloud - the "All Apps" folder I created. I'm not sure if these files/folders are technically called "database" as I'm not a tech person but I hope my examples above made it clear.
If Diarium does not work like this on iCloud, then I guess I just need confirmation that it's working as intended and that I'm not missing anything or configured it wrong.