Block an e mail domain

You cannot block an entire domain but you can create rule that sends any mail from a specific domain directly to junk or trash.

Use rules to manage emails you receive in Mail on Mac - Apple Support

Keep in mind, though, that the @hotmail domain is Microsoft’s email so sending everything to trash or junk will also affect legitimate email as well.

When blocking a email like the ones you describe, all Mail does is add the email address to a list and when a email arrives with the said address it is suppose to move it to Trash. I have a list of 3500 block email addresses on my Mac. The word "Block" is a wrong, since it isn't really getting block, just moved. If it was truly blocked you wouldn't see it at all.