btc has only fallen less than 5% from its peak. A bunch of altcoins have already dropped 20-30%, with some directly returning to their levels at the beginning of the year. If btc were to pull back 15%-20% at this time, how many altcoins would be halved and drop more than 50%?

So is playing with altcoins a high leverage of 2 times? The answer is definitely yes. Since you expect it to rise 3-4 times in a short period, you cannot be sure it will drop 70%-80% in that same period.

Moreover, the market is no longer in a situation where btc rises and everything else follows.