One should be at the bottom one at the top. I understand space on the phone is a premium but a second port would make the phone so much more usable. Wired headphones, flash drives, camera modules, speaker modules, keyboards, even connection to a TV, all could be used while charging. It’s a shame it’s not a thing, USB is extremely versatile port, but you only get one and it’s used for charging half of the time. (I am aware dongles exist)
Headset, as in headphones with a microphone. I use it for MS Teams meetings and a bit of music and it works fine.
The point OP was trying to make is that you can use USB-c for other things besides listening to music.
Since you seem to be an audiophile with a list of fancy headphones (don’t ask me, my Cardo combined with earplugs is fine for the level of listening I want to do) then wouldn’t an offboard DAC / amp that you could keep far longer than a phone, and isn’t restricted by size constraints going to be better than a built-in version?
Also, if you’re worried about e-waste maybe you shouldn’t buy so many headphones. My partner’s Sennheisers have lasted 20 years so far.