Just got my ARC-XCI55AX gateway. Plugged it in and it came to life quickly. I ran an ethernet line from the gateway to my desktop. Did a speed check and I constantly get 300 Mbps+. which is all we need (just my wife and me). However, doing a speed test with my phone/tablet on WiFi I only get 50 to about 70 Mbps -even if I am standing next to the gateway. Watched TV (YoutubeTV, had a couple of dropouts).
I turned off my old WiFi just to make sure there was no interference. Also, if I turn off WiFi on my phone and do a speed test just using the cell tower, I routinely get 1 - 1.2 Gbps!!! Any ideas why the WiFi on this thing is so slow when the ethernet is consistently OK) and why the gateway doesn't get the same speed as my phone (Pixel 8). Tried both 2.4 and 5 - no difference.