@MojangSupport I have 2 emails on my MS account, each associated with a different MC account. What does this mean when the MC accounts go away? As a content creator is this is essential.

You'll need to migrate each Java Edition profile to a different Microsoft account. However, you don't need to migrate to the same email! You can migrate one to your existing Microsoft account, and migrate the other to a Microsoft account under a totally different email. ^NS

Both emails are already associated to ONE Microsoft account though.