Get a (decent) PAID mailbox somewhere else. PAY FOR IT. There is NO “good, acceptable policies” free mail host on Earth. I won’t recommend any, people have opinions on all of them and most of them are wrong- I’m not here to have that conversation.

Buy and use your own domain. Example: custom domains are supported by some if not all of of the PAID mail providers. That way if you ever move services again, you can take your emailaddress@YourDomain.com WITH you.

Get it operational and set your old mailbox to have an inbox rule that forwards incoming mail ONLY FROM THE STUFF YOU WANT TO SEE to your new mailbox.

Now you’ll have time to switch online services/memberships to the new, proper username/email in your own time.

Once you no longer need that forwarder, destroy the old mail account and let it die forever.