Here I can help. This is my main rooExtend tread. From there you have a lot of links to the threads to all of my Roon Extensions.
The DIY page can be found at http://diy.rooExtend.com. There you also find a link to my download area to get the latest rooExtend for ARMv8.
If you like to get a Plug&Play product please visit https://rooExtend.com
If you connect a screen via HDMI to a Pi3/4 with rooExtend you will see the Roon Logo at the screen after enabling the rooExtend Roon Extension in Roon Settings/Extensions. The ZeroW2 does not support HDMI Roon output.
Best DrCWO