The 3.5mm jack on my Huawei p30 broke and I bought a USB-C to 3.5mm adapter. Unfortunately, the whole thing doesn't work plug and play moderately.
How can I use the USB-C port on my smartphone as music output?
The smartphone itself does not seem to support the USB-C port as a music output straight away, as all setting options did not help (including developer options).
There are analog adapters and digital ones. Analogs will only work on some cell phones.
So I would have to get a digital one. Are those with an integrated DAC?
Yes. Since the manufacturer never provided that the USB C port is used for audio transmission on your mobile phone, no extra DAC was installed for it.