> WhatsApp is similar by the way. Unless you enable E2E backups, they end up in iCloud/Google Drive backups and are only encrypted at rest
One of the few good things about WhatsApp is that Meta can very credibly claim that they can't access the backups (as they're not stored by Meta). Meta holds the encryption key & Google/Apple hold the backups, so at least you now have deal with two entities to get the data.
I don't think without forcing more customers to loose data (e.g. by requiring them keeping an encryption pin/key) it's possible to perform backups in a (much) better way.
I'd argue that should/could be relevant, but isn't in reality. Do two global data processors more happy to work with governments/law enforcement exist?