Let me add something else here.
In the default screen driver of @hisptoot’s image, the frame rate experience is quite poor (and I think it might also affect the output frame rate of Picoarch).
He released an experimental driver. It is said that it uses the RGB565 mode instead of the original RGB666, and has a built-in 3-bit output mode witch can reach a very high refresh rate.
Based on my usage experience, even in the 565 mode, the refresh rate has a significant improvement. When using the GBA emulator and I disable all frame skipping, it can reach around 50 frames. Therefore, adding a small amount of frame skipping can basically run at 60 frames.