DDO is not a Megascans application, so it won't share a material library with Megascans applications. You can add Megascans *.ZIP files to DDO to create a custom material or use the custom material import dialog to manually add each texture of a material to a custom material.
I tried a few searches but didn't come up with an answer. On a new machine I installed Quixel Suite, Bridge and Mixer all in one go. Bridge and Mixer seem to correctly access my Megascans library path, displaying assets I've purchased as available materials However in Quixel Suite \ DDO I don't see any Megascans in the…