@Huntleyroe
Can you be certain that the kit you are using can sustain 900mbps?
Unless the device is connected direct to the router using a CAT5e ethernet cable it is unlikely. By direct I mean using a proper 1Gbps Ethernet NIC, not a USB ethernet adapter...
As above, WiFi 5 is not going to do better than 300mbps in ideal conditions. WiFi 6 / 7 requires BOTH the router and the device to support the faster standard.
A USB 2.0 to Ethernet adapter has a maximum theoretical speed of 480 Mbps. In real-world, practical scenarios, this is limited by USB 2.0 protocol overhead to roughly 200–300 Mbps. While USB 2.0 can technically support higher speeds than Ethernet 10/100 adapters, the bottleneck remains the USB 2.0 bus.
A USB 3.0 Ethernet adapter typically provides a maximum speed of 1,000 Mbps (1 Gbps), known as Gigabit Ethernet. While the USB 3.0 standard supports theoretical speeds up to 5 Gbps, the adapter's speed is generally capped by the Gigabit Ethernet port. Real-world throughput is usually between 800-900 Mbps.
The above presumes that the device has the "guts" to drive USB 3 to its maximum.
What is the real world issue you are encountering here - how does this observation impact your use of the service. It is more than likely that you will not on a single device be able to use all that you are paying for; indeed without a high end set-up many users are paying for more than they can every use ... which is not the same as not getting what you are paying for.
Have a read of this - how fast is wifi speed supposed to be on 2.4ghz and 5ghz with 1 gig service? : r/wifi - Also do not confuse connection speed with connection / data throughput, they are not the same. "Speed" tests are actually data throughput tests.
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
