Selling any BTC in retrospect has not been the best idea. The idea of perfect trading exists for 1% of the population maybe and they do it on leverage and its their job for 8 hours everyday. Thats legitimate but its not the reality for most and looking back and pointing out the lows and highs after the fact isnt useful its destructive and misleading if anything.
The only thing to do is a consistent plan which works in the past and also the present. If you held previously and also do so now you will very likely gain, quite simple. I cant hold everything, I dont have that capital spare so Im quite fine with some attempt at trading but most of us wont be anywhere as good as we need to be.
Trading sounds simple, we just need to buy when the price dip and sell when the price increases. But the question is how do we know when prices will decrease and when prices will increase? What guarantees that when we buy, the price will stop falling and prepare to reverse? Many people also try this strategy, thinking that by doing so they can make profits or easily increase their bitcoin holdings. But the truth is not that simple, most lose money and even miss a big price increase.
I also have friends who fall into this situation, they sell when the price increases and wait for a correction to happen to buy in, but unfortunately bitcoin suddenly skyrockets beyond their expectations. As a result, they have to buy bitcoin at a higher price than they sold it for fear of missing the train.
In my opinion, there is no method that brings better results than the DCA strategy and holding until the goal is achieved.