Performance issues that have been plaguing me for a while with no solution PH315-52

Hello guys,

I have been having some performance issues for a while with my predator and I am not sure what else I could do.
The issues at hand are the following, first when I play any game that I can clearly run with my specifications I encounter constant frame drops,
some games more than others and in no particular logic.
My model is Predator PH315-52
Specs:

Intel i7 2.60ghz 9750h Coffeelake 
Windows 10 64x
Stock 16gb Ram Dual Channel 2666hz
Gtx 1660ti 6gb driver 511.65


For instance, I will play CS;GO and I will be clocking at 144fps with vsync or 240 without. 
Running the game conservatively for competitive advantage some graphical settings are turned off and overall profile is high-medium.
Mid game I will have sudden fps drops to 30 sometimes 40 for a second and then recover.
Then for instance if I play Battielfield 1 
I will also have fps fluctuations but more stable than csgo (which is weird) at higher graphical settings (ultra) but still
my fps will sharply decline to around 56-60 from 110-120 without seeming to be affected by intensity of combat or effects at the moment.

Now what's weird is this doesn't seem to be affected by adjusting my graphical settings in no way shape or form.
I bought Squad recently and if I set the game on Ultra 60 fps Low 60fps all fluctuating and freezing despite minimal or maximum graphic settings.
Other games I had issues with are GTA 5 and Rainbow six siege.

I also have random BSOD critical_process_died error 0x000000 and its seemingly unrelated to the current load or lack there off on the PC which I don't know is connected or not to the current fps issues and I haven't been able to resolve it. I researched and looked into the general ways to resolve it and no avail but PC functions fine and all components and the overall system is doing good just at times here and there BSOD pops up either when idle, waking up from sleep or exiting a game.

Things I have tried.

-Windows Restore
-Registry sfc scan and DCIM scan (no issues)
-Drivers upgrade/dowgrade (No effect on fps but better graphics and game experience in general)
-Defrag HDD 
-Optimize SSD and HDD
-Delete junk, temps
-Scan for malware 
-Clean and re-paste thermals and fans
-Use various programs to speed up the computer
-Disable a bunch of most common services hogging up memory and performance
-Change power plan settings
-Use turbo boost and overclock
-Undervolt and lower clock speed of the cpu (throttle stop)
-Use stand by ram cleaner (ISLC)
-Clear real time ram (current things using my ram in the background)
-Disable start up apps
-Disable useless windows apps and settings like cortana
-Registry edit for performance boost
-Uninstall and reinstall drivers clean 
-Upgrade the BIOS from windows update (BSOD) then recovered

I am really not sure what else to do and I haven't owned a predator before and I am just confused about these issues.

any help is appreciated!

(Thread was edited to add model name to the title)