WiFi Hovering at 250mbs on XB8T

I JUST upgraded from the 200mbs plan to the 1Gbs plan and had to change out the old router for one that would handle the gig speed, so they gave me the XB8T. I set everything up and connected my Google Nest Pro router (the main hub) to Ethernet port 1 on the back of the 8T (using Google mesh network). As I understand it, ports 1-3 are all cable of 1gb traffic and port 4 will permit around 2gb. Google’s Nest Pro is 802.11AX (WiFi 6e). Speed testing with my IPad Air 4th gen, Iphone 15 Pro Max and my PS5 max out at around 256mbs, no matter what I do. When I plug my PS5 directly into the back of the XB8T (port 2, 3, or 4) I can get around 850mbs, which is about what I expected. Testing the speed to the gateway from the xFinity app shows the router is getting around 1.2gbs, 113%. So I’m perplexed at why the WiFi is bottlenecked at 250mbs! 

Any thoughts? Anything peculiar anyone encounter with the combination of Google’s Nest Pro and the XB8T? 

I’m about to get on with tech support, but don’t expect those guys will be much help considering I’m connecting to a mesh network instead of the XB8T itself.