You have to STORE your MR setup located in the top of the MR Editor, then when you power down and back up your preset loads up where it was at. IF you don’t then it defaults to its initial setup and you are screwed.
Make sure your ADAT faders are at unity and pan them 1 left 2 right 3 left 4 right etc. Don’t forget to clock the MR from the RME as well for Wordclock which would keep you from having to change sample rates on the MR.
You can use the Cubase Morphing effects and Reverb as an Effect if you set that on the MR so it shows up in Cubase as an EFFECT.
IMO, it would make more sense to grab the RME then pick up a couple of Pres you like. As long as any of the going back and forth doesn’t drive ya nuts I guess that would work for you.
Imagine if you will Steinberg release an UPDATED DRIVER for 64 bit. FW is still there in Catalina so no release other than to EOL our MR’s