@Xalef
Just have something professional looking, something that looks like it could be someone's real name, not "xxxGayFaggot69Supremexxx@tities.club". And have it on gmail/outlook if possible.
@Xalef
If you don't use a bigger, more well know provider, you're gonna run into issues of people seeing some niche provider they never heard of and assume it's spam. Or badly made spam filters that flag your mails.
For better or worse, when you expect your mails to reach low iq office workers, that aren't into tech, you're better off with bigtech providers.