Synchronization in GoogleDrive

Hello community, since my Boxcryptor account has been canceled, I started to encrypt my files using Cryptomator but I am now experiencing synchronization problems.

Here’s what I did:

  1. I created a vault in Google Drive and uploaded my files. Works perfectly fine and I can see the vault and the files in the iPhone app
  2. I then defined, that the folder from Google drive is synchronized with an external storage connected to my Mac to have a backup stored. This also works and I can access the vault in Gdrive as well as on the external drive

And here comes the problem:
it seems Gdrive and the local folder are now stuck in a never ending synchronization loop. After the initial sync the Mac continued synchronizing and in the meanwhile I also have issues accessing the vaults.

What am I doing wrong and what is the best way to configure a vault in GDrive with an automatically synced backup?

Thanks for your help!