@Larry

I've got a few "soundcard" devices here. Drivers for "MOXF" and a Behringer UMC soundcard. So my setup is similar to yours. I do not currently run Cubase 8 - but I did for a long while before upgrading to 9. In Cubase 8 - there wasn't a huge difference although the "Devices" menu is now called "Studio". Maybe a handful of other changes - but the main functionality is all there and nothing works "better" - in terms of what you've been struggling with - between Cubase 8 and later versions.

Sometimes I've got my keyboard on the road with me and fire up Cubase without it plugged in. Cubase will default to some other driver not finding any device that loaded the Yamaha Steinberg USB driver. That's about the extent of "fouled up" things get here. I may have to manually switch back to the Yamaha Steinberg USB driver. Once I do - and "MODX" is turned on in USB mode - everything seems to be setup in terms of MIDI and audio working fine.

That's not to say I couldn't load templates that would be "wrong". I can. I don't typically use templates - that probably slows me down. I always start with an "emtpy" project and work my way up from there. If I add a MIDI track - the default MIDI ins and outs are OK.

I'm not sure if you're retiring the Komplete audio interface or not. If you are - you may want to back out those drivers from your system and unplug the unit. Not necessarily because you have to - just to clean up gear that's unused, free up those resources, and prevent confusion (for you) if you have MODX off and Cubase decides it knows better which audio interface to use.