Huawei: 3.5mm earphone adapter

I'd just go to newegg.com or amazon.com and shop around for an adapter like this one:
https://forums.androidcentral.com/e...4-_-Product%26quicklink%3Dtrue&token=sj6B4MSW

Just don't be surprised if you need to try out more than one to find one that actually works with your P30. Unfortunately, the USB Type-C protocol has become something of mess with different, proprietary standards competing with each other so there 'could' be just a simple compatibility issue you have to cope with. It's primarily a power transfer issue, but feature problems (file transfer and audio) are affected too.
https://lifehacker.com/why-some-usb-c-headphone-dongles-dont-work-1836316524
https://www.androidauthority.com/state-of-usb-c-870996/
https://www.techspot.com/news/61874-usb-type-c-get-less-confusing-through-more.html