Have been doing more searching, and it seems where this problem has been solved, it is usually NVIDIA driver issues. As I don’t have them installed, and after reading the post at Kde neon 6.3 nvidia driver - #2 by BulletDust , have now installed the nvidia drivers from the PPA.
Now by default, I can at least see the secondary monitor. It’s NQR, and when ever I change the settings, it is lost, no display on the secondary monitor. A reboot fixes that. I have tried to change resolution and refresh rate. This is what it looks like now ..
There is only 1 more setting to tweak and that is “Global Scale”, so will try that. These are the current settings:
