I have a similar issue on a UR44 mk2. My dropouts become less-frequent when I dial back my power settings (as your computer naturally will when running on battery), and when I run a CPU stress test alongside playback. Additionally, when I run higher sample rates and lower buffer sizes, the dropouts get less-frequent. It seems as soon as CPU usage drops, the audio thread gets throttled. Just as annoying as it is perplexing.
The control panel says “USB error, check manual for debugging” (to paraphrase), but the manual is as unhelpful as the dropouts. I’ve disabled all USB suspension/power saving modes, adjusted CPU states etc., so it’s not just that usual stuff where you have to tell Windows to stay out of your hair! It’s a colossal waste of resources to run 96-192KHz at as low a buffer as possible just to get audio playback that doesn’t drop out near-constantly, and months of searching has yielded no better solution.