Restore Time machine backup creates two new Volumes
After upgraded to Big Sur, I've decided to restore Catalina. I used a time machine backup. I got some problem at the beginning, but now it's ok, the only problem which remain is that there are two new Volumes named "Machintosh SSD - Dati" and "Update".
"Machintosh SSD" is the main drive.
What are they and how to remove them?