Keller23

Update — Found the issue, wanted to share for anyone else who hits this
Wanted to follow up in case this helps someone else searching for "Could not hook game process. Insufficient permissions or bad anti-virus" combined with a .NET Runtime profiler-attach failure in Event Viewer.
Root cause (in my case): A corrupted/incorrect ASI Loader file. When grabbing dinput8.dll from Ultimate ASI Loader's download table, I accidentally downloaded and used the d3d9.dll file instead (grabbed the wrong row in their download table) and had it in my GTA V folder. This caused a deep, consistent crash every single time — RPH's log would go completely silent (no error logged at all, or would silently stop mid–texture-init depending on launch method), and Windows Event Viewer showed:
Application Error (Event ID 1000): GTA5_Enhanced.exe crashing in KERNELBASE.dll, exception code 0xe0434352
.NET Runtime (Event ID 1022): "failure initializing profiling API attach infrastructure... this process will not allow a profiler to attach"
I spent hours ruling out Windows Defender, Memory Integrity, BattlEye, third-party AV, folder permissions, NVIDIA/AMD overlay software, and RGB control software (iCUE, Gigabyte Control Center, AMD Adrenalin) — none of that was the actual cause.
What actually fixed it: A completely fresh install of GTA V Enhanced, then very carefully re-downloading the correct dinput8.dll (Win64) from Ultimate ASI Loader's official GitHub releases page, double-checking the exact row in their download table before clicking. Also used xinput1_4.dll (Win64) from the same source for DirectStorageFix per its readme. After that, RPH hooked in cleanly on the first try.
Takeaway for anyone else hitting this exact combo of symptoms: if you're getting a generic "insufficient permissions" error with no clear cause after ruling out the usual suspects (AV, permissions, overlays), double-check every downloaded DLL is actually the file you think it is — a mismatched/wrong DLL masquerading as a system file can cause a crash that looks identical to a permissions issue.
Thanks again for the help troubleshooting this!