Sounds crazy when I say it outloud...
iCloud backups (enabled by default) are not end-to-end encrypted.
So while it's technically E2E, in practice you get very little protection from it because it's broken by design.
I still use iMessage because of the user experience, but let's not be fooled by their misleading E2E claims; it's all just marketing BS.
It’s an active attack and can’t apply retroactively but within these constraints they can still do it.