Rationale:
I'd like to use a DLL wrapper for edge sharpening. Playing at high non-native resolution makes stuff blurry.
Problem:
Underrail loads "d3d9.dll" via the SxS mechanism. The DLL is thus loaded directly from its "windows/syswow64" path, rather than the normal path. Please consider using LoadLibrary to load simply d3d9.dll with no app manifests. That is, before the XNA machinery starts.