I noticed that recently released Pioneer mixers are all lacking class compliant sound cards and MIDI. And I think, so do your DJM mixers except some of the entry-level ones.
My older generation DDJ-SX2 does still provide this class compliant support.
This means I need proprietary drivers and I rely on Pioneer's support policy. Also These products lack support for iOS devices that could otherwise be used in place of a laptop or as a backup solution.
At the same time, I don't see any technical reason why this should be as your older mixers did provide that and competitor mixers with similar features (on-jog screens or dual USB sound cards) still provide class compliant firmware.
As we can notice, you have just issued a warning that the "proprietary" drivers you provide aren't working with Catalina.
Guess what, my SX2 does, because it's class compliant. So as you can guess, I'll be sticking with it and consider other brands the day I will replace it. Also never considered DJM because of this annoying issue.