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..
The problem with the so-called investors is they want everything instantly, as you said if someone invested $100 per week for straight 3 years then he would be made around 42% profit from his $15,700 but these gen Z investors don't find it very appealing and they look for more fast returns where they end up getting ripped completely.
In reality, 42% is a very decent return with no risks in just three years compared to traditional investments where they could have made hardly 20% in my opinion.
Someone who wants to maximize their profits needs to accumulate a decent chunk of Bitcoin to play around, so once they get into the position they can dump half of their holdings like at the peak of next bull run and wait for the bear kick in, meanwhile they have to keep doing their investment as usual.