I very much like this idea, would be nice to be able to use a phone in more of a mini-computer manner, whereas at the moment they’re somewhat hamstrung.
I’m always surprised phone docks aren’t a thing, my work laptop has a USB-c dock that is bristling with ports that are useful.
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.