You are conflating beta with risk. Beta is just the correlation to the SPY return. There might be an asset (e.g. Oil, dunno but using it here for illustration)

You are conflating beta with risk. Beta is just the correlation to the SPY return. There might be an asset (e.g. Oil, dunno but using it here for illustration) which have low SPY correlation but still high volatility. Levering it up 2x will bring you portfolio beta wrt to SPY to 1 but give you drawdowns far greater than SPY.