You can still buy a coin during the time of the bull market and make a better profits than those that bought during the bear market. Some people buy a coin during the bear market thinking that they have bought in the cheapest price but after buying, the coin can still drop more and it continues to fall until it gets a lucky break during the bull market and that was when another investors or trader buys the coins. The market is full of surprises and you can surprised at anytime. Trading competition are good because they can make you to improve from the way you use to trade before, some traders are afraid of taking more risk as they are always too careful of how much they want to use to trade and this makes them to not get plenty profits but just average.
Bear market is very tricky and if you have never been there, you can fall this trap you just explained but are applicable to coins that are new in the market. There is no way you will buy Bitcoin in a bear market and someone that comes late to the party will make a reasonable profits than you, coins like Bitcoin has made recovery and has done a new all time high than any coin that existed in the entire crypto space, only altcoins are still struggling from their floor price.
The best way to avoid what you just explained is to buy coins that you know are capable of recovery no matter the sentiment of the marke, but and continue to do DCA with the rest of the price continuesly. Keep buying at every point in time the market continues to dump, you will reach a price where you will be average with the price and wait till the market recovery is done before money can be make back.
Bear market is kinda tricky and funny.. nobody talks about DCA enough. It's a life saver man