@RaoSumit 

Please verify the model number of Archer C6 or C6U, and we would like to know more details which will help us analyze the issue you are experiencing.
1. Are there some special activities in the network when the router auto-reboots, such as high loading or streaming? 
2. How often does the reboot issue occur? If possible, try to reduce the connected devices, modify the Transmit Power on the router to middle or low, go to Advanced > Wireless > Wireless Settings, then change the Transmit Power of the 2.4G and 5G Wi-Fi to "Middle" or "Low", then monitor again.
3. Additionally, check this FAQ to confirm more details: https://www.tp-link.com/support/faq/3032/.

@RaoSumit 

Have you tried my other suggestions, like lower down the Transmit Power, or refer to the FAQ troubleshooting suggestions? 

Do you mean the router will work fine if you don't play INR 2500 (what's the full name of this game?)? What is the bandwidth you paid for your ISP?

When you mention the router reboot automatically, did you notice this by monitoring the LED status on the router, were all LEDs flashing off then on in minutes, then the internet recovered?

@RaoSumit 

Are you using the original power adapter which is provided in the package? Can I have a picture of it, is it 12 V ⎓ 1 A?

Have you try my previous suggestions to modify the Transmit Power on the router to middle or low, go to Advanced > Wireless > Wireless Settings, then change the Transmit Power of the 2.4G and 5G Wi-Fi to "Middle" or "Low", then monitor again.

You can also try to disable the NAT boost on the router page under Advanced -> System Tools -> System Parameters page.