The correlation is due to the fact that Wall street and banks entered the market.
Back in the day people had to buy bitcoin or mine it to be able to sell it. Now they can trade with borrowed money and banks moved in, like when we had that strange case of Jamie Dimon criticizing bitcoin and saying that he'd fire anyone who's caught trading bitcoin and then we heard that they set up a bitcoin trading desk in his bank and that his daughter owns bitcoin... When these guys invest they play around with the balance sheets, they take loans and the money they can invest depends on how much the fed allows them to have. It depends on whether people deposit and save up, or spend a lot.
Then we had covid and lockdowns. People weren't spending much because they simply couldn't go to concerts, gyms, they couldn't travel, so they were saving up, scared of possible pandemic. The governments printed money to give out stimulus packages all around the world. Then lockdowns were lifted, suddenly the covid threat wasn't high anymore, so everybody began to spend and that's where inflation hit its all time high, wall street loans skyrocketed in value and they were forced to sell assets to cover them. You know the rest.
Hopefully they are out already and won't have any coins to sell after the next FED meeting. Eventually they will be out and bitcoin will no longer follow indexes.
damn, this response is kind of eye-opening. I'm going to look into Jamie Dimon on BTC some more. JPMorgan is at the top