Apple Mail bugs. Any suggestions?

My Apple Mail is acting up.

1. When opening mail in my iCloud account, the contents of incoming messages do not appear, or take an unpredictably long time to do so. This happens on both my iMac and iPhone.
2. Messages sent to myself from my iPhone do not land in my Inbox on either device, and appear only in Sent.
3. The menu bar appearance across the top of new messages has changed on my iMac. When replying to messages from my iMac, the Send button is not active. I have to press the reply button in the menu bar before Send activates.
4. Messages are inconsistently syncing across my iPhone and iMac.

I have quit and relaunched Mail and rebooted to no avail. Looking for an Apple Mail software update yields nothing.

My iMac system software updates regularly. I am currently running on Monterey 12.7.4. My iPhone is running iOs 17.4.1.

How do I solve these issues?

Thank you.

Nestor