After roasting Apple about headphone jacks, Google dumps it from Pixel 6A
Having worked on Audio Codecs and even though my livelihood depends on it, I would like to say 3.5mm jacks suck! You need to figure out how much resistive and how much capacitive load any headphone has. You need to detect if it has mic, if it does is it US or China standard. Need to make sure that the DAC and amplifier don’t consume too much power yet have a good dynamic range for arbitrary cable length. Let the phone send digital audio data along with power using USB-C and have the earpieces play the audio, it’d be much simpler IMO