I listen to mostly TIDAL even though I have Qobuz. The TIDAL MY MIX feature is killer and for me both services sound good enough.
BTW - Maybe this was figured out in the posts above. When I want to filter TIDAL or Qobuz in ROON I go to MY ALBUMS and select FOCUS. Scroll to the right for STORAGE LOCATIONS and select the location(s) that you want. A very useful feature for me since I have 5 locations, including TIDAL and Qobuz.
EDIT: I seem to have misread the question. It was about defaulting to Qobuz. Though my filter approach may work. Filter first with only Qobuz and if you cannot find want you want, expand the filter to include Tidal.