I think I’d rather use a bought put on the S&P 500 before SDS right now. Less capital involved/at-risk. But keep in mind, calling a top is difficult. Could it double top here? It could. But if it were to blow through that resistance it would embolden the algos and momentum traders.
Better to do them once its likely that the tide has already turned lower, on a rally higher within the downtrend. That downward move could last longer than the previous one.