[quotePost id=115143]I fear the dreadful "clicks and pops" while using the MODX as an interface tho...another advantage of using RME.
🙁 [/quotePost]
You shouldn't, the MODX interface and drivers are solid and they do what's required without any fuss.

Disclaimer - this is a long message with lots of content. I don't have the facility to edit - so forgive any typos.

I'll try to give you somewhat of a primer on getting this setup using ASIO4All V2. I just did this myself here in the studio and was able to get audio routed properly. I really think there's a lack of comprehension of the full signal path and hopefully this will help the lightbulb moment. I am using a different keyboard (Montage) but it is related very close to MODX. And certainly how it shows up in ASIO4All V2 is similar. Like MODX I only ever see the options for 2 channels. So other than the name being different - nothing else really is. Secondly, I am using a different audio interface. You have the RME Babyface and I am using the Behringer UMC404HD. This is a 4x4 interface but should serve as a good example of something similar to your RME. Last, I'm using Cubase 9.5 AI and you're probably using a different version and flavor. Therefore, some screens may vary but the general idea is the same.

Although it would help to have a screenshot, I'll describe the physical setup.

1) Windows 10 Laptop system at the center of this configuration with Cubase 9.5 AI installed
2) Yamaha Montage with USB cable connected between USB TO HOST port and a USB type A port on win10 laptop
2a) Montage has no studio monitors connected. Main Out L/R has no connections.
3) Behringer UMC404HD Audio interface with USB cable connected between its USB port and another USB type A port on win10 laptop
3a) Behringer has two HS8 studio monitors connected to outputs 1&2 of the Behringer.
3b) Behringer has configuration (buttons, dials) to make sure USB inputs 1&2 route out to the studio monitors. This is fairly important to hear the audio and is completely a Behringer UMC specific capability/configuration (not detailing)

Behringer's line in and XLR connectors are not connected to Montage.

What follows is the DAW configuration. There are no MIDI tracks. You're having an audio problem so there's no need to show or utilize MIDI. You may want to record/play back MIDI -- that's fine. It's just not part of the audio routing problem so I am not showing any MIDI.

<img src=" [img]

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These are the 1st 2 images that didn't paste properly:

Jason thanks a lot for the time you put to write this message, You are a hero.
I have printed it out and will study it and revert,

After you get something going, you can probably revert the MODX back to your "external instruments" topology. I don't use this for arbitrary reasons. I'm guessing whatever you're missing is part of what I've outlined and you can transfer that over to your own setup after getting the training wheels on.

I also didn't talk a lot about the driver/OS side because I assume you've got that nailed. I also didn't explain the MODX setup because I don't think there's too much there that would trip things up. However, if you have problems after getting Cubase properly configured then I could move towards the MODX side.