Don't Ethernet ANY of them (the black Halo "Complete WifI" discs) directly to Smarthub 2 imho (only do it to set them up at first).
Let them all work via Wifi only and make sure your SH2 is upstairs preferably for the biggest umbrella signal to start the mesh with.
Then have a disc directly downstairs from it, and daisy them out from that, using the My BT app on your phone to find the strongest places for them (a metre or two, or a different wall, can make all the difference).
Discs can go to partial sleep (orange light) if there's no (or low) activity in that part of your building(s) / mesh. However, I find that wandering smartphones in pockets are great jump starters, and the SH2 will give them a kick up the backside if the disc nearest to you is orange. Doesn't mean it's not working. Ideally the active ones are blue lights.
I've set up 6 black disc meshes + Smarthub 2's now in a couple of locations very successfully, as it helps to extend Eufy security camera networks in each location.