Some things to consider.
I have no issue hitting 900 megs at any time of day wired.
This requires the ethernet port of the PC to be 1 gig capable and configured correctly. A lot of USB dongles are 100 Mbit only
A lot of speed test sites are themselves a bottleneck. Some of the servers Speedtest use are not able to provide sustained 1 gig throughput.
The WiFi built into the SH2 will not go much above 300 Meg. The more devices connected to the router over WiFi, the less speed you will see even if all that other device is doing is handshakes and not actively drawing data. To see the true capability, temporarily change the SSID so that only your one device will connect.
I have experimented with a pair of Asus AX routers, one connected to the BT router hard wired as an Access Point. The other as a bridge in a room next door linked to an ethernet switch that my gaming PC is connected to. This tops out at 700 Mbit. Not bad but still can't max out the connection.
To get the maximum speed out of the AX routers I use channel 100 and enable the 160Mhz bandwidth. No other combination got me 700 Mbit.
I am told the Netgear RAX200 delivers better performance over medium distances and walls. Asus has some real problems with extremely rapid drop-off. Unlike its cheaper brother the RAX120 it does true 160Mhz and not 80+80.
It may be better to use a second router as an access point rather than replace the SH2 as I am concerned that digital phone line services will require the use of a BT router which has a phone socket on the back.
Another reason for configuring like I have is that you can use complete home WiFi for devices where 100-150Mbit is sufficient and keep the access point high 5Ghz radio exclusively for PCs that require the fast WiFi bandwidth. As I mentioned even inactive but connected WiFi devices slow down the max throughput.
