I almost went for the Atreus based on how lovely it sounds in their promo vid 
but thought I would miss the additional keys because I need to have some for dedicated audio controls - sometimes I need to quickly turn down the volume with one hand as I need to answer phone calls.
So I think I will do what you’re doing and keep the main keys to three rows, and then have the others for things like macros to open applications, audio controls, etc.
I think to begin with I am going to remove the thumb keys and try to get used to it as a just a keyboard - no idea how that will pan out tho 
Have they told you when your Moonlander is going to arrive btw?