Unaffiliated, I found migadu ( https://www.migadu.com/en/index.html ) to be extremely easy to set up and having a nice ui to work with. Gives you only the basics but that's all you need. As they say, storage space is not an issue in the 21st century, so the only differentiator between plans is the only thing that matters: the number of outgoing emails. You can have as many domains, as many aliases and as many address…
This sounds like an advertising company. A person's inbox is the holy grail of info about them.
I don't think I want to use this company for my email. Change my mind?