unable to backup after upgrade LRC 12.0.1 to LRC 12.0.>1

both on my Imac (Ventura 13.2.1 / M1) an my Macbook (ventura 13.3.1) I have been unable to backup my catalog after I upgraded LRC to version 12.1 /12.2.1 / 12.3. The error message says : check your rights and the amount of free space. 

I checked this forum and tried several of the suggested solutions, but non of them works. 

However as soon as i downgrade LRC to 12.0.1 the problem doesn't occur anymore and i can make as many backups as i want. 

additional: my backup folder is synchonized to my Nas by Synology, which works perfect when using the older version of LRC. 

I contacted Adobe help about this but unfortunatly they weren't able to solve this puzzle. 

I hope anyone recognises this or, even better has a solution for it.