When I connect a device to my gigabit network, my maximum download speed is 100 Mbps or less, If I connect to the WiFi, I get less. If I connect directly to my T-Mobile 5G Gateway via WiFi, I get well over 200 Mbps or better. I have reviewed all my cabling and my devices. Why is my TP-Link a Bottleneck, I'm thinking of redoing my network without my TP-Link, and just use the Gateway as the router.

Please Help?