I see a lot of people complaining that the Fairphone 6 doesn’t have an Aux jack.
Just use an adapter cable.
A 3.5mm Aux jack takes up a significant amount of space just to connect a few wires that could be connected through USB-C anyway, that space could be used for a bigger battery.
Even if there was a good enough reason to keep Aux it should be 2.5mm Aux and not the usual 3.5 as it does exactly the same thing but uses less space
When a headphone is connected to the USB-C port via passive adapter, the phone detects this and uses the USB-C port in a pincompatible way; nothing electrical changes.
This came with a cheap phone I bought in 2017 or so, there are no active components in there as far as I know.