Hello @Andrew Jameson
Thank you for posting this concern on this community space.
I was reading your post description and I want to share my 2 cents on this...
1-This is not expected but the only way I might think that can occur is because your personal account is linked as your recovery account for your work account, or another chance is that your personal account is used like external/guest user.
2-If you have any chance to create a new user on that tenant created using as onmicrosoft.com like the email domain.
3-You may create a new email account which is not what you expect but could be one way to get it working and when you are using this email account, by default will be the root/owner of the tenant.
I hope that works for you.
Looking forward to your feedback,
Cheers,
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