Matrix has this. You can save your recovery key somewhere to recover your chats on a brand new device. You can actually just use another logged-in device (e.g

Matrix has this. You can save your recovery key somewhere to recover your chats on a brand new device. You can actually just use another logged-in device (e.g. your desktop) to recover your chats by scanning a QR code to trust the new device. Recovery key is just in case this isn't an option.