Grace, thanks for your reply. Unfortunately, this doesn't help.
This is new behavior in 16.2. As I wrote, it appeared when I upgraded from iOS 16.1.2 to 16.2.
I don't use the Apple Mail app. Deleted it ages ago, because I found the Gmail App to be much better, at least for me. (Although I see that the Apple App Store reviews vastly prefer the Gmail App too.)
Just to see what would happen, I re-installed the Apple Mail app and logged into my gmail account. I started composing a message, and it didn't even try to suggest any addresses! I had to type the first few characters of my own address to get the address book to scroll to it. This means that the Apple Mail app doesn't appear to have the foundation of this feature of recommending addresses; although maybe it would eventually start showing this after watching me use it for a while?
The problem appears to be with the iOS keyboard, which provides suggestions (at least it does in the Gmail App). Previously, it would show my email address as the suggestion, because I send emails to myself frequently --- reminder notes. Now it shows "Hide My Email" when sending to myself, which is... both useless and frustrating.
I'd just like to turn off the "Hide My Email" functionality completely. I don't want to use it in any situation ever. How do I just disable it?