Aargh! I just discovered, the seller did not send the notebook as ordered. I ordered with NVME and he sent with a SATA SSD (checked the SSD, and yes, it has TWO nicks, which should be one (for NVME).
Tomorrow I will contact the seller and maybe return the notebook. However, I will keep you informed! There were a lot of verry good hints from you in the last days. This helped very much, especially for understanding. Can not enough say thank you for it. We will see, what happens the next days. Good, that I have a backup. Backup is always a good thing, always. Best Hans