Using own domain with a personal Microsoft account?

[Energize]

So I have recently got a windows 11 laptop and created a microsoft account on it. I currently have an Office365 business basic account for the 1tb storage mainly but also use a personal domain with the included exchange email account. Annoyingly I can't sign into windows with this account so have to sort've have it as an add on.

Seeing that the subscription price between office 365 personal which includes all the office apps plus email account and 1tb storage is not much more than a business basic account now it seems to make sense to switch over to this, is there any way to change my business basic sub to a personal 365 account or cancel that sub and use the domain with the personal email account included in the sub, preferably using that email address to sign in?

 

[Energize]

Sorry I'm not familiar with EOP1, is this in Office365 admin or MS Entra? Seems like my best way of consolidating everything is to cancel the business sub and create a new MS account with my own email domain then? Will I still have the same level of control over my email services? Like at the moment I can name changes in exchange to automatically quarantine new devices that sign into my account before I approve them and can setup aliases etc.