While  Bitcoin  investment requires patience, it doesn't mean you should necessarily have sufficient fund to invest, you invest to archieve a financial self-sufficiency... Although there are investors who are in such position but still desires to invest just to become even more.. but most people starting out dont need to build a sufficient fund FIRST just to invest all it needs  is starting from somewhere  you are capable.
At the same time Bitcoin won't care if an investor is late or early  and yes buying at the top could be somehow but with DCA everything should be balanced  overtime , if eventually there's a dip, then the Dip could cover up somehow which is better than waiting and later getting it higher if it doesn't Dip.. Besides, most waiters expectations are never met in a dip, it’s just how the mind works.
Yeah but never easy, especially when you see your portfolio going dome somehow and you still have buy more