@Barshnizza 

Is the model Archer C7 or A7 or C8? When connecting to the AC1750 wireless, can you confirm if you are connecting to the 5G network or 2.4G? If you are connecting to the 2.4G and the speed is slow, I guess there might be a lot of wireless networks or signals that interfere with the router, you'd better change the wireless channel to a clearer one to avoid the interference.

If it is 5G, you can also check if you can choose a clearer channel since 5G gets congested nowadays, and that's why the manufacturers are working on a new 6GHz Wi-Fi now.

You may also look for the QoS setting on the AX1750 and make sure that is not on or configured incorrectly, as I saw lots of users reporting the QoS may heavily limit the speed if it is configured wrong.