How to permanently delete unwanted email addresses from Gmail on Apple devices?

Welcome!

What Apple device, or does this affect more than one?

If this is happening with the Apple Mail app on a Mac computer, there is a simple way to clear old and/or obsolete addresses. Open Apple Mail and, from its "Window" menu, select "Previous Recipients":

That brings up this window with previous recipients listed:

From there you can select ones to forget, then use the "remove" button to delete them.

That's with Apple Mail app and we don't know a this point what device is involved nor how you check mail. A different computer Mail app like Outlook or ThunderBird? With a browser?

I do not see the above option in iOS on my phone and iPad. My strong suit is macOS so I am ont as familiar with the intricacies of iOS and iPadOS. If you devices are on the same Apple ID and linked through iCloud, that may get ridall the unwanted addresses from the other devices as well.

I also tend to suspect Google. If you are checking mail from a Google web page, that page controls what is and isn't stored, not Apple. Google seems too nosy to me.

Anyway, if the above suggestion fails, please post back the the Apple devices that are affected and how you check mail, so we can better narrow down the issues in this setting where we can neither see nor remotely acces you devices.

Regards, Allan (seven years older than you😉)