Restoring WhatsApp backup from iCloud Drive
I'm was in the same boat as you Viktor.
You're only missing some steps to be able to get your actual backup files. The *.icloud files are all 2kb in size and don't contain any data but are rather links to the actual files.
On your macOS go into Settings &gt; Apple ID and make sure to disable the Optimise Mac Storage option as that would give you access to the real files.
After that wait a bit as your computer would need to apply the changes and updates, restart if possible, then when you access the ~/Library/Mobile Documents directory you can see that the files are now mostly *.tar extensions which can be copied now.
Hopefully that sorts you out!