If I buy a S&P500 or Nasdaq-100 ETF (eg CSPX or QQQ) today with a lump sum for long term, would I be stuck with underlying company stocks and their performance even if some perform poorly later?

If I buy a S&P500 or Nasdaq-100 ETF (eg CSPX or QQQ) today with a lump sum, would I be stuck with underlying company stocks 10 years later even if S&P500 or Nasdaq-100 composition changes along they way, say some companies kicked out and new ones accepted? I am assuming when we buy an ETF we are buying underlying stocks in proportion, and it seems unless I do DCA, I cannot benefit from any recomposition of the index holdings.