Software Choices
When using the board, it's important to choose the right software to be able to get the most out of it. Failure to do so can seriously affect your experience, and lead you to false conclusions about the state of software support for the hardware. Therefore, please read this document in its entirety.
Use Wayland
If you want to get graphics acceleration, you must use Wayland. Panfrost is not really tested on X11. You can still run X11 applications through XWayland.
In particular, this means that currently desktop environments like Xfce, which only support X11, are not recommended.
As for how to install the Wayland versions of various desktop environments, please consult the Debian wiki.
(For Plasma, remember to choose "Wayland" on the bottom left on the SDDM login screen!)