https://www.theverge.com/2018/7/24/17606834/sony-usb-c-headphone-adapter-ec270-charge-listen-review-tests

If you own an Android phone that lacks a headphone jack, you might be aware that there isn’t a simple, universal adapter that allows you to charge your phone and use wired headphones at the same time. This most often presents an issue in cars and on planes where you want to be able to keep the device charged throughout the duration of your trip while still being able to route audio to headphones or a car’s audio system without having to deal with Bluetooth.

Many phone makers produce and even bundle a standard 3.5mm to USB-C adapter with their devices, but no one makes something like this Belkin adapter for the iPhone that lets you charge and listen at the same time. Amazon is littered with many cheap, no-name adapters, but in my experience, many of them work poorly or simply don’t work at all. For some reason, established accessory makers have refused to enter this market.