Could you please clarify that as requested? Do some file names have dlist in them?
If so, you might be telling Duplicati to look in a different spot, where there is no backup.
The database file isn’t there, but is rebuilt (ideally) from just the dlist and dindex files.
In exceptional cases of missing blocks, Duplicati might have to search the dblock files.
This could be a large download, and the last 90% of the progress bar can get very slow.
If things go normally, you get to 70% on the progress bar, and have your database back.
How stale is the other backup you restored, and does it have a (could be dangerous) stale database in it?
The database describes the destination and it needs to match. If it’s close, it might be possible to change destination to match database, but this is technically complicated and risks losing backup, which typically would be very bad, but since you got some or all of your files back, you’d just be losing the old file history.
Safer plan was given:
If that doesn’t fit, please explain. There are also unanswered questions about the files you see in B2.