The S&P 500 and the Nasdaq are both still roughly 11% higher from the pre-pandemic crash.

I think the comparison here between the $SPY and the $QQQ shows how the more diversified S&P 500 has been a great place to be (thanks energy, materials and industrials).

Many individual names have given back pandemic gains PLUS some... will the indices do the same?

I don't see this as a super likely scenario as earnings are still expected to be higher than pre- pandemic levels, EVEN if you revise 2021 earnings estimates down.