Glad to see that you got it working! Sometimes all it takes is a fresh system.

As far as the scaling goes, please be aware that most of the themes here are pretty old and were designed for Windows 7 (such as Diablo) when 1920x1080 was the highest resolution of the time, theme scaling was not even thought about at the time, some of the newer themes you may be able to scale, however I do not really know as I use a flat screen monitor and not a 4k television screen still and my native resolution is 1920x1080. Maybe some others here can give you advice on scaling.