The short funds only work at market tops, if you hold them for any time during a bull move in the market you will have losses. You need to check the past trading charts, they are a sink hole most of the time, again except for market tops. They only trade positive on panic/fear for short periods.
Trade on market fear/ downturns and it's a fast sell when it does... it's the inverse of TNA... if you had bought right before covid you'd be sitting pretty..