Although it may be tempting to turn a migrated account into a secondary account on the new Mac, that can cause problems. Much of Unix, hence macOS, identifies different users by number, with the primary admin account normally being 501. If you end up with a secondary account, that will be numbered 502, which means that all files and folders associated with that account will bear that number. If you’re then tempted to try to remove the primary admin account, number 501, that can lead to utter chaos. Only use migration to create and populate secondary accounts if you’re sure that you know what you’re doing.