OK cool. So immediate return of storage used with the cost of having to have iMessages in iCloud off for a month to delete the data before it can come back on. Means that while your iPhone SHOULD forward messages it gets to your devices, messages that you send from other devices (say your Mac, iPad, Watch) may not fully sync back to your other devices.
Interesting that turning off iCloud messages doesn't do this on all 3. I would have assumed it would sync the setting like it does the 30 days thing.
What bothered me too was that Settings --> iCloud --> Manage Account Storage --> Messages --- Top Conversations is broken. It is blank. After setting 30 days yesterday and Disabling and Deleting Messages (then turning it back on) - it's now counting messages I send.
DESPITE 32GB of iCloud Messages - I can't search for messages I know I have had in the past.
Toggling "Disable and Delete" Messages in iCloud started my phone downloading (VERY SLOWLY) the 32GB Messages. After 30 mins it downloaded about 900mb. So that's why I turned that back on and had to toggle my phone to do Forever saving of messages, then back to 30 to delete the 900MB downloaded messages.
In my mind, why charge me for 32GB of messages when I can't search them without having them on my device. And if it is going to take 16+ hours to download them all (and only when plugged in...) ... sheesh.
Had I not deleted all my messages back in 2019? 2018? I'd probably just keep them but 99% of the 32GB are videos/photos that I've already saved what I wanted to save manually.