Orbi and Sky Q

Have you actually disabled wifi in the Sky Q boxes?  Otherwise they tend to try and do their own mesh thing regardless of whether or not they have an ethernet connection, so it may be that when you thought they were wired to your Orbi satellites they weren't actually using the connection to the Orbis and were instead still trying to do their own mesh wifi (which won't be helping your own Orbi mesh).

To disable the Sky Q wifi...

Plug the ethernet cable in (and connect to your Orbi satellites in your case).

Press the ‘Home’ button on your Sky remote control.
Scroll down to ‘Settings’.
When you arrive at ‘Settings’ please do not press the enter/select button.
Enter the sequence 001 and press the enter/select button.

You will now enter the engineering menu. The message “These settings should only be changed if you’ve been instructed to by Sky” will pop up.

Now select the ‘Network’ menu. Here you have the options to separately turn 2.4 GHz and 5 GHz wireless on or off. You also have the opportunity to set the channel(s) used by the 5 GHz Wi-Fi. Make sure you turn off both 2.4 GHz and 5 GHz and select ‘Confirm’.

That should hopefuly force the Sky Q boxes to use the ethernet connection (and they shouldn't even care that the ethernet connection to the satellites is actually over a wireless backhaul).