Addendum: today Apple published an OS update: 11.5.1. I installed it. And the drivers/utility tool on top of it. Will perform further testing in coming days. I do not expect any miracle though. I think some work has to be performed on Pioneer side.
But for now: OS and Traktor were able to see and to use the sound card. Audacity was NOT able to use it. This used to work seamless.