Well I think this is more of sort of a manipulation then anything that has to do with the interest rates. Even the fed chairman hinted that there is a need to cut the interest rate in the next FOMC meeting and the price of Bitcoin pumped on the day of his speech but after that it has been a continuous dump. I think this is to take out weak hands and them we may see another all time high in September.
Manipulation is inevitable and it happens in every financial market, not just bitcoin. But as far as I know, bitcoin price reacted positively after the Fed chairman's statement and then quickly dropped sharply because a whale sold more than 24,000 BTC, equivalent to more than $4 billion.
Furthermore, Powell only hinted that the Fed would cut rates, but he did not say for sure that a rate cut would happen in September. Therefore, we should not be surprised that the market remains cautious and not overly optimistic.