What does the backup actually contain?! And what doesn't it?

I was not sure, so I just performed the procedure again and even gave Roon as fresh an new install on my MacBook and used a USB stick for database migration to avoid any network issues
and YES, this time I can say for sure that I restored the backup successful before logging into my account.

What has improved? Roon now correctly displays “recent records”.

What did not improve? Roon is “circling” and “adding” and indexing for hours now and probably still some hours to come and I absolutely don’t get why that is.

Roon performs two missions. The first one is finished faster with the complete read-in. The second job is to improve metadata as good as possible, to recognize objects accurately takes more time.