LSX are Roon tested. Did you try to “roon” them directly?
Almost the same issue with LS50 Wireless. The only solution for me with LS50 - downsample to 24/96.
I also have Digi Pro+ (HiFiBerryOS), use it with Hegel H390 (until H390 becomes Roon ready) and it works perfect:
I should try to test Digi Pro+ with KEFs 