According to [docs][1], `SetBrushOrgEx()` is supposed to affect the *next* brush that is selected into the device context. It might be interesting, then, to see what happens when a brush is selected into the DC after calling `SetBrushOrgEx()`.
[1]: https://learn.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setbrus...