Monterey mail not syncing with iOS 15 mail

Ever since I upgraded to Monterey, I have been having syncing issues with mail. I can find mail on my iPhone (iOS 15), but I often cannot find it in the Apple mail app on my Mac. Example: received newsletter from source...read it on my iPhone. Tried to go back to it tonight on my Mac, and it's not in there. When I go to my iPhone, it's there. I am attaching two screenshots to show ... 1 of the email on my phone (showing that it's in my iCloud mailbox), and three examples of the searches on my Mail app on my Mac (where it is not showing). This is just one email example. It happens a lot...is anyone else having this issue? Found a fix? I can't track it down. It's an iCloud email account and I've had it for years. Just started happening with both upgrades. I suspect though that it has to do with Monterey.