Personally, I do not like ideas of "going all in" to investments...
To me, it sounds like gambling and or trading rather than investing.
Even though I get the idea that reserve funds can be saved up in order to have extra cash that goes beyond regular DCA buying to be able to inject into your BTC investment at various points along the way, especially at various dippening points.
You are right but investment is now the only way to be profitable for everyone, trading or gambling without experience is not very profitable, if one invests in Bitcoin now, it is almost certain that he will be in a profitable position within a few months.
Also as per your suggestion if one trades and gambles intelligently then more profit is possible, but most of the wise people can't do these things by following the right rules.
Even if someone started investing $100 per week into BTC near the top of the first 2021 peak and through the second 2021 peak, and he continued to invest consistently and persistently that $100 every week for the past 3 years, he would be profitable right now since he would have had invested right around $15,700 and he would have 0.558 BTC (which would be worth around $22,320), and personally, I think that would be a great place to be for a person with that level of a discretionary/disposable budget..
We have an exception to if we are interested in going all in at once with our investment, this could be only possible when we make the necessary research on the previous performances of the market and the coin we are having in mind, then compare the past to the present and if you could speculate something out of it, whereby it's profitable to buy the dip and invest when the market is extremely bearish, in this situation, you can go all in at once and invest, but never make a mistake of investing on anything else aside bitcoin.
It is therefore mostly advised that when choosing a particular pattern of accumulating our bitcoin asset to hold, we should make use of a pattern that best serves our interest, using DCA or going in at once with the market when it is dip, buying and holding at the bear season is profitable enough provided that we can hold.