The first way has been done in studies for years, maybe even a decade ago.
Earlobes.
I'll search for the papers later and link them.
https://scholar.google.com/scholar?q=earlobe+blood+pressure
https://www.todaysmedicaldevelopments.com/article/wearable-b...
I've always wanted a Garmin linked ear-cuff device that uses the earlobe for heartrate and blood pressure and then doubles as music playback or alerts from the watch. You could even do body temperature from the earlobe reliably.