For point 2. about a tiny assistant device: Apple filed a patent for a biosignal sensing device last year. It’s future AirPods for monitoring brain activity and other biosignals.

US20230225659A1 - Biosignal Sensing Device Using Dynamic Selection of Electrodes - Google Patents

A wearable electronic device includes a housing, and an electrode carrier attached to the housing and having a nonplanar surface. The wearable elec...