Use Throttlestop to undervolt (It'll help A lot with performance and thermals) The sweet spot for this particular CPU is -125 for the Core and -48 for the Cache, anything over will give you stability issues. Also, Undervolt the iGPU and Intel GPU by -50. It'll make a difference.
On the main throttlestop menu you can tick the Speedshift EPP and change the value number from 128 to 0, this will make your CPU run at maximum speed 3.9 so you'll get an amazing performance in all your activities not just gaming with high FPS, but this will also generate a little more heat. use this while it's plugged in and create another profile with the value set to 128 to use when your notebook is unplugged and running on battery to save some battery and get a decent performance. Throttlestop will switch automatically between the two profiles when you choose this option from the throttlestop's settings. Also, make sure to untick BD PROCHOT it'll remove a great deal of throttling whether it's thermal or power.
Plus, set the fans to max speed while playing if you haven't already to avoid being thermal throttled and make sure you're using the "Balanced" power plan in Windows while gaming, this will lower the possibility of getting power throttling.
* One more thing, you mentioned that the thermal issues appeared recently so it might also be dust or something blocking the fans and vents, i'd suggest cleaning it up if you can. + Check if the power adapter is working correctly because gaming on battery will cause throttling and performance issues.
Let me know how it works out for ya and good luck. 😄
