Hi Danny,
We are mainly responsible for general issues of Office desktop applications, but your question is more related to the purchase choices of Microsoft 365 subscription.
Are you a Global Administrator if you subscribe a business or enterprise plan, such as Microsoft 365 Business Standard? It's best to contact support for business products - Admin Help.
Generally, when you subscribe a home plan for Microsoft 365, such as Microsoft 365 Family, you do not need to a domain, but need to ensure computer is connected to the Internet at least once every 30 days to renew activation.
In order not to affect your use of Microsoft 365 due to other circumstances, please contact Microsoft on chat or by phone to have a confirmation about this issue.
Thanks for your understanding.