It is possible but only g3d, z3d will be overridden by other shaders.
This however has more impact on performance than desktop use and you will need the vr hacked reshade dll to use (I only know reshade works, though there was vr enb for skyrim)
As for d3d9 conflict sometimes vorpx complains about it but works, sometimes it makes a game crash, sometimes you are able to rename it to any other dll to work. There is a list of dll names that windows applications load by default and with these post effect tools you can use those to make game hook post fx tool while not having vorpx complain.
All in all you have to try it yourself and success can vary per application and your dedication on trying to make it work.