Every time the market has a phase as you said, sometimes it goes up and sometimes it goes down and also experiences periods of correction. but in my opinion if you are just an observer then it is a big mistake for traders who want to take advantage of every market condition because there are so many altcoins that we can choose to trade. because each altcoin does not have the same movement as one another. so take advantage of every market condition.
Whenever the price of altcoins is going up, show that bull run is about to enter the market which is the best time to sell to accumulate profits, and whenever the price is going down in the market, show that bear run is about to enter the market for people to start buying altcoins from the market.
If you look very well, you will know that the majority of people watching the market price right now are those that are hodling altcoins for the bull run to come before they can trade to earn good profits.
ETH and BNB use to move the same time, but not all the bull run they used to move at the same time but if you can take the advantage of top altcoins in the market, you will be happy when the bull run hit the market running because that is the season to earn well.