10 accounts sounds like there are actually lots of aliases, which would be free.

Regardless, I’m a happy Fastmail user as well, just to add another anecdote.

Yes, Fastmail accounts correspond to the number of users you have. Each user can set up a virtually unlimited number of aliases.

I have also been a happy Fastmail user. Reliable and easy to configure.

$5/mo for 10 accounts is $50/mo in total. I don't know where you got the $500/mo from.

And that is a very reasonable price for a core service like email and not selling you data

You’re absolutely right; I feel exceptionally dumb! Don’t get the downvotes?