I usually put in postmaster@<yourdomain> (e.g. postmaster@heatpumped.org). Eat your own spam, idiot.

Never thought of that, now it will be the first thing I'll try.

Mailinator is great if the website wants you to click a link or enter an OTP to verify whatever it is that they verify.

I usually put in <ceo name>@<major ad / search / social media platform>