Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I have signed up for office 365 home - which gives me 5 users (wife, kids, mum)
At the same time I signed up to outlook premium which also allowed me to register my domain name.
I know that outlook premium is no longer available for the "free" outlook.com (i.e. email only) but the description below does indicate "premium outlook.com" - so perhaps it is included?
https://products.office.com/en-gb/office-365-home
Worth investigating? It may just be that I signed up at the right time but I can confirm I am using Outlook.com (and all the office products) under O365 home as is my family.
Good luck!