The cheapest Infomaniak tier is about 25€ per year. The sign up process is a bit confusing because by the end you have like 3 passwords or something but once you get it going it’s a decent service. I don’t use it myself but I set it up for my parents and after initial setup it has been working without issues.

https://www.infomaniak.com/en/ksuite/service-mail

Wish that would happen to me :(

Wait I don’t understand how changing your CNAME to A records resolved your problem. Did your wife’s computer simply not resolve the CNAME records?