A Raspberry Pi 4 and 5 is just a bit different in the hardware, but they uses the same "Raspberry Pi OS".
The new thing with
Raspberry Pi OS
is the switch from X11 to Wayland and this is the cause why many old (X11) tutorials doesn't work.
I have no solution for
Dakboard
at the moment.
I would recommend you to take a look at MagicMirror2 (
https://magicmirror.builders/ ) That is similar to Dakboard and its free.