Trying to delete messages from icloud storage while keeping them locally on my devices.

I've tried to follow instructions I've seen in other threads but they don't seem to work. I have several devices. I am pretty sure that icloud storage of messages has been turned off in every case. On my desktop, I get a message saying disble and delete messages from the messages app. That doesn't seem to have any affect on the icloud storage. On the portable devices, if I go into icloud storage, I open the (turned off) messages app, and it just gives alink saying "undo disable and delete."

I don't want to flood the small bit of remaining storage with more messages by turning imessage styorage on, and I don't want to delete my message archive from my devices (at least the desktop mac). This shouldn't be so tricky... I keep getting adverts to pay apple for more storage space. 80% of the stuff filling the icloud drive is messages. Help!