Earlier quoted context omitted.
WhatsApp backs up your encryption key to Google Drive by default, meaning it's far from end-to-end encryption. It's more like end-to-Google-to-end. If you choose to decline this default, your conversation partners probably haven't. Signal had a catastrophic bug that would send random images in your camera roll to random contacts. If you want your private photos sent to your family members, use Signal I guess.
>WhatsApp backs up your encryption key to Google Drive by default, meaning it's far from end-to-end encryption. This is a lie[1]. If you don't enable backups yourself, you loose your messages. You can enable E2E encryption for your backups. WhatsApp is vastly superior to Telegram in terms of E2E encryption. Telegram can read users messages on their servers and they are not even trying to tell their users to enable E2…
Regardless, chances are your contacts have enabled the Google backdoor if you haven't.
>WhatsApp is vastly superior to Telegram in terms of E2E encryption
That's why CVE-2020-1910 enabled attackers to steal your entire message history with a single image message. Has Telegram had similar catastrophic E2E exploits? Nope.
>Telegram can read users messages on their servers
Google has your WhatsApp "E2E" private key by default -- meaning it is NOT end-to-end encrypted. Telegram's E2E Secret Chats have no such backdoor.