Yes, it's true that buying crypto on a bear market is very good, but it should be noted that keep investing with good financial planning, never invest with money that you don't want to lose.
This is suggested very well for the altcoins but when you put it in bitcoin, you only need to have the right guide which is to invest only what you can afford to lose to avoid regret and confusion since the recovery of the price this time is not fast than we used to have in the last 2 years. A bear market might sound opportunity to others but in reality, the best way to take advantage of it is to find the best coin that will have a high chance to recover once the bull market comes back because not all of the coins in the market will recover in the future for some of them will remain at their lower price forever.