You shouldn’t give out your real email address. I instead use randomly generated email addresses that forwards emails to my real one. I can easily deactivate any forwarding email address and therefore stop any unwanted emails.

It works really well and also has other benefits like for example knowing who sold your information if you start receiving spam.

You also gain a bit of privacy and security from being a tiny bit harder to track and your credentials being less valuable in the case that the company you gave the random address to has a data breach.

This video explains the concept very well.

If you are willing to compromise I would recommend Betterfox as it breaks far fewer sites while still being better than the default Firefox profile.