@999frogs 

Hi,

If you don't mind the effort, then perform a Factory Default Restore on the AX50 and then test the speed again without adjusting any settings on the router except those that are essential for establishing the connection to the Internet. (also don't log in to TP-Link Cloud at this point)

If the speed is still slow, then I guess there is nothing more you could do.

In case you get higher speeds now, then you would have to go forward like, change setting -> test speed -> change another setting -> test speed, and so on, until you have found what causes the speed to drop.

Anyway, I only have a 200 Mbps-rated Internet connection that averages around 220 Mbps in reality and I get this speed wirelessly as well as wired with my AX50 router.