While I personally like having a headphones jack and would be quite happy with a larger smartphone with a larger battery and headphones jack, a lot of people do care a lot about size. I've seen women in particular complaining about the fact that their clothing often has limited or small pockets, and large smartphones don't play well with that.

The headphones jack was never designed to be incredibly space efficient.

That means smartphones have extremely limited space. Plus, if you want it to be modular -- which is how Framework permits for the option to have a headphones jack on their laptops -- you need even more space if you want to maintain structural strength of the phone.

I think that the best bet, if you carry headphones with 1/8" TRS plug, is to just leave a USB-C adapter plugged into the end, as that places the space on the headphones end, where there isn't a space constraint:

This is minimalist, optimizes for size:

https://www.amazon.com/Digital-Headphone-Adapter-Converter-Samsung/dp/B07KJ87HYJ/

This has a passthrough port, so that it doesn't tie up your USB-C port:

https://www.amazon.com/Headphone-Charger-Adapter-Splitter-Charging/dp/B0CSKF9XSF/

This has both a headphones and microphone port:

https://www.amazon.com/ZOOAUX-Microphone-Adapter-Splitter-Compatible/dp/B0CDX38TRN/

This has a headset jack, if you use a headset with integrated microphone:

https://www.amazon.com/Vcddom-Premium-Adapter-Headphone-Compatible/dp/B087CS4T4G/