deleted iMessages are still showing on Mac OS Monterey

I suspect there may be a design issue going on. The behavior seems to be that swipe to delete conversation in iOS is actually closing the conversation, not actually deleting the messages and conversation.

Thanks for the response but unfortunately nothing worked. Just for clarification...

1. Links you shared about blocking messages on Mac, iPhone and iPad are not related to the issue in my post. My issue is deleting on one device should delete from all devices.
2. The link you shared about Accessing messages on all devices is exactly the behavior I am expecting, except it does not work as described. All devices are signed into the same iCloud (have been for years), have checked security, 2-factor authentication, etc. Have tried logging in and out of iCloud on Mac, same on iPhone and iPad. Have repeated the same in different combinations. Have also tried signing just messages out of iCloud. Suffice it to say I have been researching this across the web including all of the apple support articles, but still no joy.

Thanks for the persistence, but the instructions you shared do not always work for me. Tested again today. Steps taken and related behaviors....

1. on iPhone - press/hold on message bubble to get "more..." menu. select all messages, then delete all. Message removed from iPad immediately. iMessage removed after pressing sync now on Mac. Success.
2. on iPhone - swipe to delete a different conversation. Warning message that "Conversation will be deleted on all devices", accept and proceed. Message removed immediately from iPad. message not removed from Mac.
3. on Mac - select a different message, then clear transcript. Then delete conversation. Click sync now. 1 message successfully deleted from all devices. 1 message still on iPhone and iPad. Waited some time, clicked sync now. Still no joy.

So it appears that I am going to have to live with two things:

A. Messages shown on Mac and iPhone and per the instructions on Apple site are mostly incorrect.

B. It is ridiculously, overly cumbersome do delete message conversations on Mac. And I don't buy the "its to protect the user from mistakes" argument. There is a simple set of actions on iPhone and iPad. Swipe, Acknowledge, Done. If this is protection enough on these other devices, then why not on Mac?

yes iCloud is enabled. Have tried turning off and on. Have tried sync. None have helped.