Hello!
Software part:
This roon-cec-controller-extension is not up-to-date (I haven’t updated for 6 years!), Roon changed their plugin framework a while ago and I did not update this.
As I am still using it (although it is out-dated, it still works…) it is on my to-do list, with no ETA.
Hardware part:
I am using an old NUC (see My Perfect Roon Core/Bridge), but I think newer NUC models are no longer compatible with the Intel NUC HDMI-CEC Adapter so you probably need the USB - CEC Adapter.
Ben.