Cannot remove outdated email address auto-populating

Somehow an outdated email address is attached to a contact and I cannot get rid of it. The email I am using on my iPhone is a personal domain that I use Gmail to check. The outdated email address is NOT saved in my contacts. Not on my iPhone contacts. Not in contacts on Gmail. My suspicion is it's a Siri or server suggestion that is saved on a device (like an old Mac computer maybe?) No matter what I do, I keep sending emails to the wrong, outdated email address because it populates automatically when I type in the person's name, and I don't even notice it's going to the wrong email address because the phone shows me their name under "to" and not the email address. Even though there is NO reason this name and this email address should be attached to each other according to my contacts!

How do I remove this email address completely so that it stops auto-populating on my iPhone? The email address does not come up on Gmail so I know the problem is stemming from an Apple product. I am logged into this email account / syncing contacts across several Apple devices (laptop, desktops, ipad and phone). On one of the computers, I opened the contacts app and I found the outdated email address come up, attached to the name and it was labeled "server suggestion," I deleted it completely! But that's why I think the problem is stemming from this same issue just on another device, maybe one I don't even use anymore and have no access to... Is there a way to get the contacts to stop taking "server suggestions" from Google? Thank you for your help!