RAXE450 5GHz band averaging 750-950 Mbps

For the WiFi client devices, what was the PHY rate of their connection?

If in the same room and on the 5GHz band with the AX features turned on, it should look like this.

On your specific WiFi adapter, it should give you around 1.8Gbps real world throughput from a 2402Mbps PHY rate, though there are exceptions. If extremely close to the router, e.g., within around 8 or so inches, speeds can drop due to receiver overload leading to corrupt frames, thus the router will get a ton of overhead from frame re-transmissions, common on any AP that uses attempts to use a full watt of transmit power, though if using DFS channels, due to extreme FCC restrictions, they get forced down to 250mW which can be used at closer distances.

Outside of that, also head to the router page, and click on the "Advanced" tab, and then click on "Show Statistics".

Make sure the 2.5GbE port is showing a status of "2500M/Full"