Microsoftthere is no solution to this, they outright don't care.
Unless your specific problem is that you want move entirely to business for your domain, in which case they can..i believe disable the consumer microsoft account that exists on that email to fix your issue.
Want to have a custom domain on exchange? yeah.. you'll need an outlook.com email address completely separate to register your windows license to, you cant use if for Xbox or anything else considered "for public"... got a problem with this!? sure they'll bounce you round 12 departments who all claim you need to talk to a different one... support is fundamentally broken. After a year of trying to explain the issue and being told to go to user voice, I emailed Sayta Nadella, whoever moderates that email account forwarded me to a complaints exec... who .. essentially told me not to use their business service... so i moved off the platform that day.
Learnt the hard way to stay away from microsoft products... they used to be decent, it used to be that only in development circles you would find difficulties because it was always "follow the shiny thing". I don't know what went wrong, but now support is the same, they dont give you options, they decide the microsoft way to do it, and if you happen to have a common case that doesnt quite fit in their narrow solution you have to just find a workaround. dissapointing to say the least. fortunately they have nothing there isnt an alternative for now that Steam Deck exists.
an extermely bitter former user.
