Not parent, but I too am paying for email for years and am very happy with FastMail. You can see a lot of work is going into it lately now that they're independent again. Can't recommend them enough.

FastMail, indeed, and I love it. Something insanely gratifying about being able to file support tickets and rapidly get answers for an email service.

Fastmail for features and ease of use. Protonmail if you want security.

I use;

https://kolabnow.com/

and

https://posteo.de/en

and use Postbox as my mail client. All great so far and only costs a few £'s a month. Probably less than lunch for a day or two.