ok I attach the log.
In the meantime, I continued to test.
I think I partially understand the problem.
It happens when you already have a site created from a backup.
In practice, despite assigning a new domain name, the domain with the backup name remains in Local> Overview> site Domain.
example: mysitebackup.local, while in “Local Sites”.
While the correct name of the new domain “demosite” is displayed in the “Local Sites” sidebar.
This causes an error when creating a new copy from the backup, because every new site created from the backup always assigns the same domain.
Finally I took a final test. I deleted everything from Local and recreated the site from the backup and it was successful.
At this point I exported the created site and dragged it into the zip file. This created a functional copy with correct domain name.
The main site, however, always remains with the domain name of the backup.
If I try to create the copy again using the backup from drive, the error comes up again, so I assume it is as stated above.
Also I noticed another thing, that the setting to change the site Domain does not work, in fact changing the name keeps giving an error. I don’t know if it’s always related to the main problem.