Sir JJG your story about your Bitcoin accumulation journey is impactful when you said that there was a time when you don't have extra money to purchase Bitcoin but still any Time you have some extra money, even if is $20, $100 or $300 from some kind of an inflow of cash you got you would immediately divide that amount in half, and buy bitcoin with half, and put the other half towards aspects of your monthly budget, this shows how dedicated and committed you are in your accumulation
You are right when you invest with such money that you won't have to worry about if Bitcoin price is going up, down or sideways it will help you hold your Bitcoin for more years to come, people that hold form 2015 or 2016 till date didn't worry about Bitcoin going up or down and that's because they invited with just there discretionary income.
If I understand properly, @JayJuanGee did not say that it is a bad idea to continue accumulating your Bitcoin when you are short on funds and to do so with whatever little cash you have left over. However; I believe that there is a saying that you can start building up your Bitcoin holdings with any amount you can afford, even if it is only $10 to $20 per week or month. But investing such an amount of money will not provide high returns. And if expenses are preventing you from investing a large amount of money, you should try to reduce them.
However, only individuals who are new to Bitcoin will be worried about market movements, and they must learn from those who have been accumulating Bitcoin for years and continue to hold. Using the DCA strategy to accumulate should be done consistently for a long period, whether monthly or weekly. It is unsafe for any individual to do so for a short time.