Answer: Not likely to happen. 😭
After years of pestering, January 2018 Parallels posted a formal statement and explanation regarding DirectX 11:
Why isn’t DirectX 11 supported in Parallels Desktop?
One of the mandatory DX11 features is called “compute shaders.” The
name “shaders” usually refers to graphical functions that calculate
the appropriate color and brightness for an image, but “compute
shaders” are quite different. Compute shaders help the programmer to
more easily take full advantage of the many processors on today’s
graphics cards, primarily by broadening shader capabilities beyond
pure graphics to more general calculations, which can be done on a
Parallels implements DirectX emulation by translating it to the
equivalent OpenGL function, since OpenGL is implemented in the macOS®.
Unfortunately, the version of OpenGL in the macOS does not have
compute shaders. There is nothing for Parallels Desktop to map DirectX
shaders to in the OpenGL framework in the macOS.
The macOS does support another style of compute shaders in the OpenCL
framework. (Don’t let the similarity in the names “OpenGL” and
“OpenCL” make you think they’re similar. They aren’t. In fact, they
are competing “standards.”) Unfortunately, however, OpenCL on Mac
isn’t as robust and doesn’t cooperate well with OpenGL.
Besides compute shaders, there are other features missing in OpenGL on
macOS, which means there are additional “feature parity holes” with
DirectX. There’s simply not enough functionality to translate DX11 to
in the functions available in the macOS.
Apple® started pushing its own Metal API recently, which is universal
for Mac computers. Only time will tell if Metal will give the
Parallels Desktop programmers what they need to support DirectX 11.
Stay tuned, but don’t get your hopes up for any major change in the