People who short or just recently invested are the ones mostly affected the most, in terms of profit anyway. For other perspectives, it can vary ig? I mean someone making plans to invest, reinvest or sell at a certain point may have their plans ruined if the price suddenly drops off outside of their expectations but those are highly subjective in the first place since it doesn't really rely on just the price itself but rather on the individual themselves so might not really count.

Other than that idrk? Big industries who buy Bitcoin I reckon can endure losses of sudden fluctuations of drops so I highly doubt they'd be affected. Big whales are the same. If it was a relatively big dump then it'd be everyone anyway, so I don't think it matters to ask who is affected the most. I guess if there was an answer, then it'd be people who were late on selling trying to minimize their losses.