GDPR isn't in force yet. You're right though, they are asking for trouble as they can't even identify who accepts the privacy terms so any and all PII collected will be illegally obtained. The Sonos seems to collect a lot too.
Seems like good sport to get a 4 year old to accept and upgrade then sue the pants off them for listening to your house and uploading recordings. Wouldn't even have to ask the child, they'd be led to accept terms just by trying to listen to a song in the new app which won't play until the upgrade happens.