This sort of analysis is very common on the stock market. 'Santa Claus Rally', 'Sell in May and go away' and other sayings get repeated every year but in reality, any backtesting of the data shows that it would have been impossible to make a profitable strategy from them.

I'm also less than convinced about any correlation between the stock markets and crypto. The crypto markets being much smaller are more susceptible to large swings on very small pieces of news. So basing any analysis on past data is even less reliable than in stocks.