The trouble is you need to enable flow offloading in LUCI, I believe it’s under the firewall settings or else you’ll be pretty speed limited regardless of wired or wireless. I believe the default for the C7 is to have it turned off.

I believe if they don’t have flow offloading enabled 250Mbps is exactly the speed they should expect. It’s been a while since I’ve used the C7, but I believe that’s precisely the limit of what I was able to get without offloading. Now it worked just fine for me as the connection was only 25/3Mbps but that’s neither here nor there.

TP-Link makes a 5 port gigabit unmanaged switch for less than $20USD. It’s great. You can get it with PoE for $50.