Actually, the DXVA2 mode is the one thats wrong, you just have everythign setup backwards
madVR doesn't mess up black levels. The thing with the DXVA mode is that once you start using the DXVA mode, the GPU Driver starts messing around with the image, and it screws up the black level, which is why its inconsistent.
Somewhere in your GPU Drivers settings you have probably configured something that causes this.
The fact that the black level is otherwise wrong for you just means that your PC outputs something the TV does not expect.
You can change inside madVR if your TV wants 0-255 or 16-235, and you can usually also change this in the GPU settings, however, it is crucial that you only change it once. If your GPU is setup for 16-235, and madVR is *also* setup for 16-235, then you get it wrong, because both compress the colors, and you get double compression. Either set both to 0-255, and you get full 0-255, or set one to 16-235, preferably madVR, and leave the GPU at 0-255. If that doesn't work, you can try to inverse it, set madVR to 0-255 and let the GPU do the compression to 16-235.
If your TV (and GPU) support it, i would always vote for setting both to 0-255, however i've had some issues with Intel before that it didn't work properly to set it 0-255, it always switched back to 16-235 when using HDMI.