It should be noted that I am not saying that buying strategies are not important. However, I am saying that all buying strategies are the same (good) if the funds used to invest in bitcoin are discretionary income.
On the contrary not all buying strategy are good, you spoke of lump sum strategy and DCA accumulating strategy, but you never spoke of dip buying, and I can confidently say that those investors that focus only on dip buying aren't doing it the right way, because by waiting for the dip they are going to miss a whole lot of buying opportunities that may present itself in the market, so it's not a good strategy.
The best way to invest is to use either the DCA accumulating strategy or the lumps sum strategy, then if their is a dip in the market, you may decide to buy aggressively then, only if you have the reserve funds to do so, but waiting for the dip only as a strategy is a terrible way to invest in Bitcoin.
You are right waiting for the price of bitcoin to drop to make a purchase is also a less than ideal strategy to do. But in my personal opinion, for investors who already have more than 85% or more of their targeted bitcoins, it is possible for bitcoin investors to wait for a price drop in bitcoin when they are going to make a purchase. Because basically the investor has almost touched the bitcoin target that they will have. So it doesn't matter if the investor waits for the DIP to make a purchase. And what is not recommended is for beginners or investors who don't have much bitcoin to do it. Because basically the accumulation journey is still far away, so it is certain that waiting for the DIP when making a purchase is not the right thing to do, because they will definitely lose a lot of momentum. Therefore, regarding the buy the dip strategy, I think this strategy is only suitable for investors who already have 85% or more bitcoin from their target portfolio and is not recommended for investors whose bitcoin portfolio is below that.