Got the Archer AX55 Pro a few days ago. However struggling with it on some devices. Laptops/Computers are all running blitzy fast as expected (both wired and wireless).

Have PS5 connected to this router via Ethernet cable. However have noticed speed is decreased (as compared to previous router, a Fritzbox) - getting 324Mbps down, and 38Mbps up. 

Unplugged the Archer AX55 Pro, plugged back in the old router (Fritzbox), and get 630 down, 159 up. And games are connecting to the server quicker. 

I initially had the PS5 under Parental Control, but since removed that so it is "standalone" and not tagged to a family member, however speed remains more or less the same (low).

I am on a fibre gigabit unlimited plan. 

Set up remains the same, e.g. the exact same cable and switch between the routers and the PS5. The only variable that has changed is the router itself. 

Anyone have ideas of what to try next? I.e. has anyone come across this problem before? This close to returning the TP Link and returning to use the Fritzbox. 

I will factory reset the TP Link router, and ensure firmware is all up to date, and then test the PS5 again.