let’s be realistic here, buying the dip is one of strategies of accumulating bitcoin,
Yes... But a wrong strategy to employ when you're new to bitcoin since you don't have any bitcoin, you should be more focused in building out a descent portfolio for yourself with consistency and commitment and not just timing the market to buy a dip.
and there are different type of persons into Bitcoin accumulation, there are those that their nature of job keeps them very occupied that most of the time they forget to buy on a regular basis,
This is where commitment and good management of cashflow comes in comes in, if they're committed to their accumulation journey, they would make their regular buy a priority and allocate funds to both their regular buys and building out backup funds as soon as they've received their income and removed their expenses. Let's be frank here, no one is too busy for what he/she prioritizes.
those set of persons, as their incomes arrive, they might decide to lump sum,
Without first removing money for their expenses?
How are they even sure they have such large discretionary income to lump sum?
I would consider such actions inappropriate. The first thing an investor does when the income arrives is to remove his expenses budget from the income, then he can invest and build backup funds from the remnants which would be his discretionary income.