> The only thing I've really been a bit tempted by is Lidar on Apple

Maybe in that vein, one thing I wish phones would do to differentiate themselves is just add more sensors. I want my phone to be the tricorder from star trek. iPhones should have first party support for generating point clouds and measuring distances using lidar. Their microphones are probably already calibrated, why not expose that as a decibel meter. Same for light sensors. Phones used to have IR emitters, why not add those back in?

Also the iPhone still only has 240fps slow motion, I've found samsung's 960fps really useful in capturing transient phenomenon or even measuring mundane things like LED flicker.

Conversely the Pixel seems to be the only one shipping with an IR thermometer, and they'll probably remove it given most people don't seem to care. That's something I would've found useful in ad-hoc situations where I've had to make do with the back of my hand.

Air quality detection (especially pm2.5, CO2, and CO levels) would be great but I don't know if those sensors can be miniaturized enough to fit.