@P1pp5 

You can do that. I tried at my house, Satellite Deco establishes Ethernet backhaul link through powerline adapters.

Do not expect high speeds with that. In my tests, I couldn't get more than 100Mbps on powerline link, and that will be the speed limit for any device that is connected to Satellite Deco which uses powerline adapters.

Other and preferred options are Ethernet cable, and also Ethernet over coax if you have TV cables at your place you can reuse for Ethernet link.

@Alexandre. Thanks for your reply. Which powerline adapters do you have? TP-Link seems to quote the latest powerline adapters at max 1,000Mps. The ethernet ports on the XE75s are gigabit, too. Is there any other reason why that sort of speed would not be achievable over standard residential electrical wiring? (We do not have coax.)

A Wi-Fi 6 or 6E backhaul is able to provide connection speeds of up to 9.6Gps between satelites. So almost ten times the wired backhaul rate.

So I guess the only valid use case for a wired powerline backhaul would be if a wireless connection between satelites was really struggling.

How can I check the connection speeds currently being achieved between my XE75 satelites please? Is this possible with the Deco app?

All that I can currently see for each satelite is the signal rating, which is being described for each simply as "Fair".

  @P1pp5 

For my tests, I used ZyXel PLA5215 kit which claimed to deliver up to 600Mbps speed. It works with Deco, but with speed that is way below their claimed maximum. Which is to be expected from powerline technology in regular household.

If your Satellites report Fair link speed, you probably don't need powerline adapters. If Satellite Deco is too far, reports Weak link speed and can't be moved closer, powerline is an option but with a lot of caveats - and not just speed of connection.

There is no way in Deco app to get actual link speed. All you can do is connect device to a satellite (and very much preferred that to be wired device connected by Ethernet cable to Satellite Deco Ethernet port) and run speed test on that device. 

Assuming you have fast Internet connection that is not maxed before the link between Deco, you'll now have an approximation of actual link speed from that Satellite Deco.