The Huawei P20 and P20 Pro do not have a 3.5 jack connection. The headphones are connected via the USB-C connection.
Can the P20 Lite also use the USB-C connection for headphones, although there's still a jack connection?
As long as the headphones / adapters have an integrated DAC (sound card), they should also work on a P20 Lite.
The P20 Lite supports OTG and that also includes audio devices.
If the headphones want to use an internal DAC from the device, it will not work on the P20 Lite. The DAC from your device is only connected to the headphone jack and not to the USB port.