Why iCloud Messages uses too much storage, and stores phantom deleted data in apps: Solved!

I've seen many posts about this but no answers on this forum. Calls to Apple support on this tend to be pretty useless. 

Fortunately, I found this Reddit post, which offers real solutions and real community input. I also posted this long comment about this on Reddit and I won't repeat it here.

THE PROBLEM: If you use multiple devices, iCloud essentially saves photos, videos and any large files IN iCloud as well as ON each device. It seems to count EACH COPY toward your iCloud storage, meaning it's very easy to fill up on the 5 GB free plan due to multiple copies alone. 

People are also routinely confused because "top conversations" generally amount to much less than the total Messages storage space used, and it's very difficult to impossible to track down all the offending files.

ONE SOLUTION: If you want to use iCloud with Messages, you have to regularly prune your devices by (1) going into iCloud storage and deleting any large Messages attachments; (2) go into local storage for each device and delete them again; (3) go into your deleted Messages folder on each device and EMPTY them. This works but seems to require nearly constant maintenance and a lot of redundant work. 

(Some people also like to set a time limit for storing text threads so that Apple deletes them regularly but I don't want Apple to make those decisions for me, especially because some text convos have a lot of sentimental value.)

The easiest and IMO better solution (esp if you have limited storage and don't want to pay) seems to be to turn OFF iCloud for Messages altogether. As long as you have message forwarding on, it seems you will still have most functionality. 

I think you may have to delete conversations separately on each device but IMO this is a much smaller issue than all the work described above and would not result in the same storage issues.

ANOTHER SOLUTION that I didn't totally follow seemed to be endorsed on Reddit. It's a combination of turning off iCloud for Messages on one device and then manually deleting a bunch of related stored items in iCloud Messages. 

I couldn't follow it but opted just to turn OFF iCloud for Messages on both my devices.

As far as I can tell, all my messages still exist on my phone and computer. They seem to be syncing fine because I have message forwarding on. 

The other issue with iCloud is that even fully deleting all files related to apps (Notes, Voice Memos, everything reall) still leaves apps super bloated by phantom deleted files you are stuck with — with the only solution being to delete and reinstall the app. 

Between those two issues, Apple seems to want to force us all to pay for iCloud storage rather than give us a seamless solution that actually makes sense. 

As a result, I've turned off iCloud for nearly everything except Reminders and Find my Phone. I am using Google Drive for cloud-based document scanning and just airdropping Voice Memos and other necessary files between devices when I need to do that.