Room acoustics (untreated walls, tiled floors, etc.), overwhelming bass output (from subs or speakers) and speaker placement can affect how much difference you can perceive between components and cables. If room acoustics aren’t a concern, then..
When doing a comparison, based on my experience comparing DAC, don’t go flipping back and forth between inputs during one song. At a minimum listen to the entire song, make mental notes. Repeat the same with the other dac.
Better yet, give yourself a whole day with dcs without listening to McIntosh inbuilt dac. Then switch over and listen to the same playlist. Give your brain more time to acclimate to one dac before switching.
I heard a McIntosh DA1 dac and unless DA2 is some sort of a revelation, it can’t stand a chance against a better DAC, and it shouldn’t take dCS to beat it.