I think it's better to buy Bitcoin now. The market is in a state of uncertainty, and if it goes lower, many altcoins will not survive.
But if you want to take a chance, then now is a very good price for dot.
If Bitcoin recover half, some altcoins will recover 1 time or 2 time. Suppose Polkadot price fall dip more than half, yes we can take this altcoins opportunity.