If your PinePhone 3th party adapter does work consider remote desktop via VNC from your PC

  1. VNC on PinePhone (how to):

https://danct12.github.io/VNC-on-PinePhone/

  1. VNC Server for Pinephone:

https://www.kirsle.net/vnc-server-for-pinephone

  1. how to setup a VNC server on your Pinephone with PostmarketOS:.

https://wiki.postmarketos.org/wiki/VNC

4: SSH and VNC to PinePhone:

4. Example how to access a Raspberry Pi from a PC via VNC:

5. VNC viewer and server:

Write in the comments below how you managed to access your PinePhone from your PC.