I am having the exact same problem:
Vorpx 19.3.1.2
SteamVR 1.18.21
Windows 1903
Using the Steam version of Red Dead Redemption 2
Tried the alternate hooking method, and deleting the documents folder. I get the exact same warning messages as Flandy, and no hook. Vorpx seems to be working great on other games, but not RDR2. I am launching through Steam I don’t know if that matters or not?
Just wanted to bump this thread and bring attention that this may be a common problem among the steam users?