Can’t you get email from them?
Or get an AppleID, that gives you an email address. https://appleid.apple.com/
Sorry, am not sure what you mean by this. Are you trying to obtain an email address where e.g. firstname.lastname @provider.xyz matches your wife's firstname.lastname @swissworkemail.ch?
I have a somewhat generic combination of Scottish first and last names (even in Switzerland there are multiple people with the same names) and since firstname.lastname @gmail.com wasn't possible I created firstname.lastname.ch @gmail.com. Would this be an option for your wife?
EDIT: nevermind it seems the problem is external email address being blocked. In this case, can't your wife just rely on her phone for email?
I can recommend https://proton.me/about
or gmx.com (English) or gmx.ch (German only)
they all work well for me.
I also never use names in my email addresses. Instead, I use weird combinations of words that aren’t normally used together. Massively reduces spam and hack attempts.
with gmax, you're probably referring to gmx.ch - this is a very popular provider here, but I don't like it. I've had my emails from gmail blocked by GMX.
I also recommend proton.me - try a free account to see if it gets blocked.
Indeed - I've moved my custom domain stuff from Google to Proton when Google started charging for the service.