I made a sequence of Av mode for testing.
In LRT3.4 I can process it with HG wizard, but the outcome is not good enough.

So now I want to try if LRT4 can do better, but I found that the HG wizard key is grey (disabled?).
Do you know what's the problem here? I use LRT 4.2. Thanks.

Holy Grail Wizard is for sequences shot with the Holy Grail Method (M-Mode, changing Camera parameters while shooting).
When you shoot in A-Mode, you don't need it, therefore it's disabled. In that case, the new Visual Deflicker will be your friend.