“Many of the time that BTC and the VIX were in an inverse relationship back in 2018, and the way how they relate to each other has regularly been shifting. So, the ideal strategy would be using aggregated data, such as the combinations of other correlations and exchange/asset flow data, to achieve positive results.”

https://www.newsbtc.com/2019/09/19/bitcoin-grows-in-periods-of-low-equity-market-volatility-report/