As I've pointed out in other skins, there seems to be no blurriness around your text or roundels, is this the specific model? Or something you do differently than other skinners?
Something I've begun to do is relying less on pre-existing typefaces for creating code markings and drawing my own markings from scratch. Fonts tend to blur more at most sizes and requires some cleanup to keep looking crisp. In this particular case, 3, U, J, and R use many of the same shapes and curves. Making it very easy to copy portions from one base letter to make more complex ones.
Could it be due to the extra detail provided by working with a 2K skin vs the older 1024x1024 skins?
Yes, the larger size plays a role in making clearer markings and allowing for more detail, but on the 110 the difference is not that great since the 110 is so much larger than other fighters. For example: the fuselage cross on the Bf 110 is only 119x119 and on my BF 109's I use a 101x101 cross. Now when the 109's get updated to 2K those crosses will be scaled up to about 200 pixels and all the markings will be super crisp. The 110 needs the extra space, but have a look at the new Ki-61 or F4F to see how much a small aircraft benefits from a 2K file.
