I set up two TP-Link AC1900 for a client. The remote is connected on an ethernet cable. I added it with EasyMesh.

I've set regular and guest WiFi networks. The regular WiFi network delivered full speed at the remote end, in this case 100 Mbps. The guest WiFi network gets maybe 15 Mbps.

A Roku at the remote end says that the regular network is "excellent" signal strength. The Roku connection test says it gets 100 Mbps speed. The Roku is perhaps 15 feet from the remote AC1900.

When I try to connect to the guest network from the Roku, it says "guest" is "fair" strength, and when I run the connection test, it gets maybe 15 Mbps.

Before I turned on "Smart Connection", the Roku wouldn't even connect to the guest network. Oddly, the Roku still shows the "_5G" SSIDs even when smart connection is on.