I don't want to go back to find the messages again. Some were for IOS 15, and some for earlier updates.
Yes, Gmail and Exchange have all my old messages. The Mail app had them, in the in box, before the update, but now they are gone. It happened on my iPad and my iPhone at about the same time, I assume because of the updates.
I tried deleting Gmail and then adding it again, as suggested in an earlier exchange, but that did not give me access to the old messages. I may have done it incorrectly. If that is supposed to work, I would appreciate clear instructions. The Mail app on my Mac still works, so the problem seems to be specific to IOS.