For this user the cause seems that it was retpoline since he solved his problem in the way he describes, perhaps any other who has the same problem should try his solution in case it helps.
Alcohol has disabled the Kernel Import Optimization on Windows 10 with 188.8.131.5201 and later, surely someone can come up with a way to implement the Virtual AHCI controller without disabling this?
That's what you say in your other post. You mean that Alcohol disables Kernel Import Optimisation or that you have to disable it in order to create a virtual drive? If it is the first then perhaps this is the simple reason that Alcohol disables Kernel Import Optimisation (if it can't create virtual drives with it) and I don't know if there can be a solution to this.
The users change disabled all mitigations for spectre, including kernel import optimizations,
Alcohol itself disables only Kernel Import Optimizations,
Meanwhile the nearest competitor software doesn't have to at all, so Alcohol-Soft devs are taking the quick and easy way.