Not sure about DC/Marvel apps sorry, I don’t use them (I usually avoid apps which have a dependency on the Play Store). I use Comixology and Tachiyomi for my comics instead, and don’t have any issues with either of them. That said, generally speaking apps that aren’t optimized for e-readers can in fact behave a bit odd, but this is why Boox included a per-app optimization tool, thru which you can customize the DPI, background color, fonts, refresh type etc for each app. For instance, Comixology has a dark background by default which doesn’t look nice on e-ink, so you can tweak it via Boox’s tool to display a bright background instead (the comics themselves display properly).