More and more manufacturers of mobile phones drop the 3.5 headphone jack.
Another trend is replacing the micro USB connector with a USB-C connector.
Today you can get dongles with USB-C in and 3.5 analog out.
This means there is a DAC build-in.
A perfect solution to connect wired headphones to your mobile that lacks the analog jack.
However, there is also a USB-C Audio Adapter Accessory Mode.
In this mode the device sends analog audio over the USB!
All you need is a passive adapter.
Obvious, USB-C is the most analog sounding digital bus!
To the best of my knowledge, there is nothing you can do as a user to invoke Audio Adapter Accessory Mode or avoid it. This explains why a passive USB-C - headphone adapter works on some mobiles but not on others. The same applies to USB DAC's.
A bit more about USB and this Audio Adapter Accessory Mode can be found here.
List of USB-C adapters