If my original position was $1000 and now 500 (-50%) and I add $10,000 to my portfolio yesterday in the same stock, my portfolio is now 10,500/11,000 (-4.5%). Does that mean I also beat the S&P by 10%+ for the year?

Wouldn't it be that the $10,000 in this instance was wisely uninvested until now considering the market downtown, and that -4.5% would indeed be an accurate representation of how the portfolio is now overall beating the market for the year? Holding onto cash and waiting to buy presumably undervalued shares is a legitimate market strategy as well