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.

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.

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