Imo i believe the optimum allocation is subjective based on individuals income, country, goal, and attitude towards risk.
The DCA amount allocated for the month
I guess doesn't have to be once a month but could be spread across the days in a month especially during a correction or dip.
One of the benefits of accumulating bitcoin with the DCA strategy is to control your emotions, and your idea of accumulating bitcoin with the DCA strategy cannot help investors control their emotions because they are interested in timing the market to buy the dip. Anytime they accumulate bitcoin and there is a little dip, they will regret buying bitcoin at the wrong time. The DCA strategy should be done in such a way that we set out a particular date to accumulate Bitcoin monthly. For instance, we can set out to accumulate bitcoin every 5th of the new month since monthly salaries are paid at the end of each month, and sometimes it might be delayed. And when the date comes, we can accumulate bitcoin even though the price is increasing or decreasing.
Buying daily could be a burden and therefore difficult to implement. If the purchase is made on centralized exchanges, consider the withdrawal fees which is expected to be made daily, that a lone can become a big amount of money when you check it in a month time of daily withdrawals.
If we are purchasing our bitcoin on a centralized exchange, that doesn't mean we should be withdrawing our bitcoin anytime we purchase bitcoin. We can withdraw our bitcoin when we have accumulated bitcoin worth $500-$1000, so we will spend less money paying for the centralized exchange transaction fees.