Another alternative is if you are busy on schedule or don't use some exchanges feature about DCA, what if left some limit order on some prices you want?
Let's say you decided to do DCA and already analyzed it too, then you know that you have a busy schedule, then use the limit orders of exchanges and set the prices on which want you to buy.
A good idea, however I wonder how busy can a person be to not be able to perform a DCA strategy? Even if we assume the strategy was performed each week, buying some bitcoin will at worst take you a few minutes, if someone cannot really spare a few minutes each week to perform this strategy then I wonder about their time management and how serious they are about this market.
As anyone that wants to reach some level of success on almost any activity needs to be willing to invest way more time than that.