Looking further into using VIX as a market timing tool, one problem is that the pre-Covid bottoms in the VIX were way lower than what we've experienced in 2020/21. Right now at 17.81 the VIX looks super low based on 2020/21, but in the pre-Covid years the VIX routinely based down around 12 (2018/19), and was even down under 10 in 2017.
So as the markets return to their pre-Covid 'normalcy' (if they do), then the behavior of the VIX might also return to a more normal pattern, and what seems low now for the VIX (17.81) may not correlate with a market top.
Oh well, back to the drawing board. There is always the RSI indicator and MACD, supplemented by the rabbit's foot, dice roll, pronouncements from the Mojo Man, etc..