Laptop turns off exactly after 30 minutes, full details given

Hi All

I have done everything I can for weeks and no answer. I searched internet and did what people have recommended and still no use.

My laptop is Dell Inspiron 7559 4k touchscreen and about 4 years old now

While I was playing a game, my laptop froze, 20 minutes later still nothing, I held power button and still nothing, I had to remove the battery from the laptop to finally switch it off as nothing else worked.

I reinstalled battery and started using it as normal, suddenly it turned off after awhile and now it turns off exactly at 30 minute mark.

Laptop works, everything works, I can still play games, watch movies, I'm making this post on this laptop but at 30 minute it will turn off lol.

Now things that I have done to fix it

Checked power settings / dell power settings

Cleaned the laptop

Replaced thermal paste

Replaced thermal pads

Currently its running without these

Removed extra hard drive from laptop (using SSD hard drive for windows installation)

Removed Battery from laptop

Removed wifi hardware from laptop

Removed sound hardware from laptop

Removed case/cover from laptop currently bare boned

Removed extra RAM, tried each ram individually

even without all the above, laptop works and still turns off at 30 minute.

Removed CMOS battery on and off and tested. still turns off after 30 minutes

Disabled Nvidia graphic card via driver

Updated BIOS to oldest and newest - same problem

Full re-installation of windows 10 on SSD

Ran laptop health check / diagnostics via Bios nothing found.

Updated all drivers

even in bios mode, it turns off after 30 minute

It cannot be hardware, I believe its some sort of program that is making my laptop shutdown exactly at 30 minute but dont know how to fix it.