Yes, it depends on market conditions, so it's good if you have a strategy of doing multiple DCAs for each price level (this will readjust your buying levels).
For example, at a price level of $16k to $20k, each of your purchases is $100 (DCA-1). Once the price level goes up $20k to $24k it will be $60 (DCA-2), etc. In this case, your portfolio should be separate.
That would make sense if you knew BTC was going to range between $16k - $24k.
But without the ability to predict the market it's risky. What if it never drops below $24k (or whatever level you set), you'll never buy BTC again and, unable to save the fruits of your labour, you'll end up being poor.