Do you use Roon to manage your music--ie., core is running in the InnuOs?
If you use Roon and jettison your existing chain you will now need a dedicated Roon server.
After many different configurations on Roon core integration (two different Lenovo i7 laptops, i5 and i7 full sized pc's, and finally a mac mini), I have found the best result from running Roon core on the InnuOs Zenith MK III. I would NOT sell the InnuOs if I were you.
If you got rid of all your current stuff in favor of one streamer you might satisfy your desire to simplify but you will likely take a step backward in performance.
Perhaps keep the InnuOs Zenith MKIII and your current stuff and maybe get a new rack or way to organize the layout?
Of course if you don't use Roon then the Lumin sure seems like a convenient way to go.