Just used method three to get access to a Windows 8.1 machine from a thrift store, so I could reset it. It did not work with a user that was signed in via a Microsoft account, but was a super way to do it with a user with a local password. From there I could delete the other account. I think you can also add users with admin privileges this way, so it should be a tool I try whenever I have Windows issues.
You can read more about it here: https://www.makeuseof.com/tag/3-ways-to-reset-the-forgotten-windows-administrator-password/