While bitcoin was trending sideways in a triangle for 3 months, a bunch of obscure defi alts gain a lot of momentum.
Bitcoin broke out of the triangle and money started flowing out from defi alts and into ethereum.
Money trickled slowly trickled out of ethereum and into BTC, and when BTC got close to breaking a huge macro resistance at 10.5k, BTC gobbled up much of ETH's gains
Institutional investors started pouring in after BTC broke 10.5k, making BTC extremely correlated with gold for a few days.
Money from BTC floated back into ethereum