IANAL but I think anything that can be potentially personally identifiable, with tracking associated, would be. If you have “registered” your appliance (for that extended warranty), you have given them your details which are then associated with the device.

Say you are Samsung, you have a fridge with a camera on it that keeps track of what’s in the fridge “for the user”, so they can see inside their fridge even when not at home. Now add in some image recognition, automatically tracking exactly what’s in the fridge, how often it’s used, when it’s running low. Now you have some of the most valuable consumer data possible to sell to data brokers. That is defiantly covered by GDPR.