Hey there.
It's fairly hard to predict the future when it comes to the markets. So, although we can take historical returns into consideration, it's important we don't put too much reliance on them to make decisions about the future. A prime example of this would be how much Big Tech has driven the outperformance of the S&P 500. Historically it looks nice, but if tech were to struggle over the next bit here you'd likely see the S&P 500 struggle relative to even something like SCHD.
SCHD has really struggled over the last bit here and I can't help but think it's due to higher policy rates. If we look at some of the top holdings, 3M, Pfizer, Verizon, etc, they've all struggled over the last bit here primarily because of high policy rates.
Over the long term, I would prefer to own SPY, VOO or some other variation of an S&P 500 ETF. It really has been the premiere index to own for US exposure.
However, it is possible on a dip in policy rates we could see SCHD rebound which makes it a short-term bounce back opportunity.
I guess to answer your question as simply as possible, I wouldn't be in a rush to exit SCHD at this point in time. I view the S&P 500 to be the superior long-term investment, but right now there is no doubt the S&P 500 is expensive while the general mix of SCHD's holdings are cheap.