@SushanT1593 

Hi I don't mean to come across condescending but when you try the speedtest.net platform via mobile or via PC, 

There is a option where you can change the server based on your location, 

I'm uk based and we have many different servers. 

I'm on 940/110 (Bt fttp) and I noticed that I was getting low speeds via wifi and via pc once I did 3 tests via each server to give me the average  I found that maybe 5 out of the 20 servers I tried gave me the speeds that I was paying for. 

With some servers i was just lucky to push 250 down via wifi or via lan. 

Maybe trying changing the servers and see what ones are able to get you to the speeds you pay for then do a series of tests between them and you should find the most consistent. 

This is what you shoud get when you click on the change server option. 

depending on your location if your UK based then you'll probably get the same list as me but if you located elsewhere then you'll have a different list 

  @Basboi85 I have been to many places in my city over a period.

But I have recently encountered this situation of speed when I'm in need.

Firstly I was using a plan lower than 200mbps which was working fine and crisp.

After upgrading my plan over this same router over 500mbps I'm just getting speed up to 500mbps via LAN after doing some changes over QOS which I did some research over Google. about AX50/AX3000.

I can't get my actual speed in any kind of Mode in QOS more than 200-250MBPS when activated.

Over Wifi, I tried many servers in my city the speed varies a lot ranging over 200-250MBPS only.

But not a problem for uploads over Wifi which shows me around 400-450MBPS every time

  @SushanT1593 "This is what I'm experiencing with a WiFi 6 router..."

  @SushanT1593 

Hi, what is the model number of your TP-Link router?

It is suggested to read this troubleshooting guide and try to disable the QoS and Parental control on the TP-Link router.

  @Marvin_S I have specified in the earlier comments...AX50/AX3000