It's not selling that should be done at this time, but buying. Of course, if you already have the money, then the most appropriate action is to buy.
For those who already have Bitcoin but no more money to buy more, patience is a must.
By the way, investors are different from traders. Those who choose a long-term approach will not sell but will instead try hard to buy in a market like this. What you mean is for those who trade. Trading is indeed complicated.