if SEC not approving ETF was a sure thing then there could not be a drop by the time they reject it. a drop or a sell off happens when people didn't expect something bad to happen, but if they start expecting it to happen then they would sell sooner than the actual incident and by the time the "incident" happens there is nothing left to sell and there will be only buys rising the price.
I’m willing to buy bitcoin at a lower price, the future dump is already expected especially when ETF didn’t approved by the SEC. We may experience another drop but who knows, maybe the market will react to that normally.