What happens if I reset end to end encrypted data? What will I lose? Potentially older texts or more.

What happens if I reset end to end encrypted data? What will I lose? Potentially alot.

If you dig in the literature for this issue you eventually get this:

"Messages in iCloud also uses end-to-end encryption. If you have iCloud Backup turned on, your backup includes a copy of the key protecting your Messages. This ensures you can recover your Messages if you lose access to iCloud Keychain and your trusted devices. When you turn off iCloud Backup, a new key is generated on your device to protect future messages and isn't stored by Apple."

I'm not sure what the ramifications of the key change are but I would guess that messages on your phone might re-populate icloud because most people in the prior version of this question didn't notice a change, but it's very possible your phone only stores 2 years of messages and iCloud stores many years. If you need anything from long ago, like messages from dead friends or family you want to keep, then I would make sure you have a local copy on your mac. I believe there are such copies and I will post back if I can find a way to make sure my history has a safe copy that I can load or if I use some 3rd party software to do the same.

Or you can try tech support but this is what it was like for me, which is normal. According to the 3rd tech I talked to - which is probably still an entry level tech (I told #2 he was lying when he said I needed Big Sir to login to iCloud so he transferred me) - he has never heard of any messages getting deleted but didn't really know. He was also pressuring me to take the chance, but I know better. That's what one hour on the phone with Apple usually gets me - someone guessing and usually the 3rd person. I got to a 6th person on chat after 3 hours the other day but they were still entry level! They can never be bothered with looking through 3 hours of support and want you to re-explain it every time. I think it takes at least two days to get advanced help these days. Maybe they don't even have top level help anymore because all of my issues require them but no luck.