The month of march has been a bearish period for Bitcoin since it's history and a lot of whales predicted it's price to go below 60k and probably rise again after March in the anticipated halving towards April.
That's because most of these whales are people who experienced the previous cycles. People who watched bitcoin make new highs a year after the halving time and time again, but never before it, so it's obvious they'll expect this to continue.
Also, Tether recently released about a billion dollar USDT and afterwards we saw the price of BTC surge above its previous price of 62k to 63 and currently 65k plus.
The main driver is ETFs that are constantly buying. Tether could be contributing if they really hold as much bitcoin as they claim, because that would mean they always have to get more BTC to print new USDT, but who knows what they're really doing. We'd need regular audits for that.
I don't trust Tether.