I understand.
You could look into getting a domain either way, it really is pretty simple — you go to a registrar website (I like porkbun.com), choose your domain name and purchase it. To get the email stuff going, it's just a bit of copy pasting between their guide and the domain's control panel.
Like I said, this domain stuff is useful outside of Migadu and similar services, but for a more 0-config option, I think disroot is alright. You also have a mailbox.org and StartMail (from StartPage).