Hi AvinashKokkiri,
Thank you for reaching Microsoft Community. I'm sorry to hear about the thermal and flicker issue you are having on your Surface Pro 7.
Whenever the device heats up, do you experience also a drop on its performance like freezing or lag aside from the screen flicker?
Does it happened only when the device is plugged in or also when running on battery?
It is normal for the device to feel warm especially when it is under a heavy load , running updates or plugged in but it should still maintain its performance. If the device overheats, it will shut down and display a thermometer icon on startup (if not cooled). You may also see this page for more details: Caring for your Surface battery (microsoft.com).
Kindly try running these steps also and then observe if the issue persist:
1: Run Surface Diagnostic Toolkit
See: Fix common Surface problems using the Surface Diagnostic Toolkit (microsoft.com)
2: Check for Windows Update
Go to Windows Settings > Update & Security and select Check for updates
Make sure all updates need are installed including Optional updates
3: Update drivers and firmware
Check what is the current OS Build of your Windows version by going to Settings > System > About.
Go to Download driver and firmware for Surface, choose Surface Pro
Then click the link next to Surface Pro 7 then click Download on the next page.
Choose the .msi file that matches your current OS Build and click Next.
After downloading, run and install the .msi then Restart.
4: Run System File Checker Tool
See: Using System File Checker in Windows (microsoft.com)
Hope this helps.