Yeah you are right. The smart thing newbies can do is build the habit of buying regularly rather than trying to figure out exactly when the price will be at its lowest. Trying to wait for a dip is like chasing a shadow, it keeps moving, and you will never catch it perfectly. In terms of aggressive buying, i will say newbies should avoid that for now, and just focus on their DCA, till they have accumulated enough and gained lots of experience along the way. Then lastly, it's not just about having your DCA funds , what matters is how consistent you are. Some people might decide to buy 3 weeks straight then lose focus and skip maybe another 3 weeks till God knows when , then they come back again and repeat the same step. Doing that won't put you in a good position.
If your discretionary income is not constant to enable you buy every week. There's nothing bad if you buy whenever, you have your discretionary income even if you skip one or two weeks because you cannot buy bitcoin when you don't have a discretionary income. As you are trying your best to buy whenever you can, you should be working on improving your income either by getting a second means of income or learn a skill or go and study to get a higher qualification so that you can have a consistent discretionary income and DCA consistently till you reach your bitcoin target.
It's when you have your discretionary income available and you feel reluctant to buy bitcoin weekly, regularly, consistently and persistently is when you are not serious with your bitcoin accumulation. However, it's better to accumulate bitcoin once in a while than not investing at all.