Just manually copy the bookmark file on the Win 10 Pro desktop machine to the new Win 11 Pro desktop. stored in a file located at C:\Users%username%\AppData\Local\BraveSoftware\Brave-Browser\User Data\Default on Windows.
I did, several hours ago in this grief. Same result.
The only thing that makes any sense is that somehow the file got corrupted when the OS on the old machine got zapped by the OS update. But, that doesn’t really make any sense after all, does it?
I tried to import brave bookmarks on one phone to a new phone using brave. No dice.