If we are looking for a PinePhone alternative, which can be used for mobile Linux computing, the information we show here could help you. A Raspberry Pi with a 5 inch display might be easier to handle with for non-coders than the PinePhone.
The screen size of this display is close to the size of the PinePhone screen, and this video shows how to use it with a Raspberry Pi 3.
The screen in the video is 800×480, we can find eventually a newer screen with higher resolution, the video has recorded three years ago.
The PinePhone screen size is 5.95″ LCD 1440×720
the electronic GURU , creator of the video shows us which keyboard according to his view is the best for Rasberry Pi. He also shows us how to use the the touch display with a pen.
For comparison, here is a video with a similar demo for a LattePanda V1 running windows 10 with a 7 inch touch display: