Outlook mail with custom domain

Hello,

I would like to use a custom domain for my outlook mail account (private), but I have a question/problem regarding that:

Can I use a domain that doesn't have mailbox?

For example avoro.eu is selling you a domain for €4.99/year without mail.

Is that enough for the free tier at microsoft?

Because if you're using the mail service of the domain provider you have two drawback:

1. You have to trust the privacy of the providers service for your private mail

2. You have to pay a high price just for the mailbox. For eample at strato.de, you have to pay €4/month just to have mail and a domain and that's way to much for just a custom domain for me.

Sincerely yours

David