Cannot delete iMessages from iCloud - annoying warnings all the time on storage

I get annoying messages on iPhone, iPad and MacBookPro that my iCloud is almost full. After investigating it appears that iMessage was using 4.6 of 5 GB available

I went into all the devices and deleted ALL photos and videos in the messages. Warnings on some deletions stated that they were being deleted from all devices, this was NOT the case. I had to go into EVERY device to delete some attachments.

It's now 6 hours later and iCloud still shows the same usage. It even shows a small file being stored, but I cannot find this and my iCloud folder shows no items. Can someone explain how to clear the messages from iCloud.

I have seen some postings to "delete and Disable", but uncertain if I do that, and then re-enable if the few iMessages that I want will be re-uploaded to iCloud to be saved so that when I purchase a new phone or iPad the messages will sync again.

Thanks in advance