@Ashik61
Hello, thanks for reporting the heat issue.
Please attempt the below to observe the outcome:
1. Feel the router top and bottom, how about the temperature? If it is what the environment should be, that should be normal. Ensure you put the router in a well-ventilated location or mount it vertically on a stand that permits the free flow of air, and use a fan to cool the router, a regular fan or USB fan is fine. As long as the router is not placed in an enclosed area then it should be fine.
2. Set the Wi-Fi Transmit Power to low (if the setting is currently set to high), and see if this helps.
3. Turn the Wi-Fi off completely and feel the difference of the heat output.