Logic Pro: Why is my audio interface (Behringer UMC1820) unusable unless I launch with Rosetta?

I have a 2021 MacBook Pro (with an M1 Pro chip), and a Behringer UMC1820 audio interface. The Logic Pro FAQs state that an interface that doesn't require third party drivers should work on Apple silicon, which means the UMC-1820 should be good to go. But if I launch Logic in Apple Silicon mode, it's all but impossible to get the UMC to play back audio.

I've been testing on the demo projects (e.g. the Billie Eilish tune), and after a few seconds of playback through the UMC, the audio stutters and skips such that the time barely advances. I experimented with all the audio settings, and the closest to usable was when I set it to use only 2 cores (the minimum). All other threading settings (including Automatic) were also unlistenable. In that configuration, the audio was playing for the most part, but skips were still quite common, certainly nothing I could rely on. The other audio settings had little or no effect on the problem.

I was about to call it a bust, that the hardware simply isn't compatible. But in a last ditch effort, I launched Logic Pro with Rosetta, and as far as I can tell, the problem cleared up. The interface plays smoothly using automatic/many cores, and at a wide range of I/O buffer sizes (I tried as low as 64). Anyway, I got to see that the hardware works on my new Mac, pure plug-and-play, just not in M1 mode.

As I understand it, the latest Logic Pro has been thoroughly optimized for Apple silicon, and if I'm running in Rosetta, those optimizations are not utilized. And Logic Pro is where I planned to do my most intensive work on this brand new beast of a MBP. I don't know how long I can depend on the Rosetta workaround, the way these things get abruptly phased out. Is there a known fix for what I'm experiencing, or a fix on the way? Or is the UMC-1820 taking a short path to obsolete?