FINALLY !
Guys ! I think i figured it out , the main culprit is Whatsapp's backup !
- Simply delete the existing backup from your iCloud Drive.
- Restart your device.
- Make a new backup.
- Restart again , it should fix the problem.
Now just in case the problem is still not solved for you. Because it didn't for me for the first time either.
Do one thing.
Go through your Whatsapp backup and get rid of all the super extra things. Like media that are forwarded many times , files that are too large to keep. Just filter few of the items. And then repeat the first process again.
Now that all the extra stuff is dumped , make a new backup and see if it solves the issue for you.
I think Whatsapp data gets corrupted or gets buggy if you are keeping it for a long time. Deleting a few extra things and making a new backup somehow refreshes it. It worked for me. Might work for you too.
All the best , stay well.