Your main problem is your computer is overheating. Have you ever disassembled your laptop to clean it out? Replacing the thermal paste between the CPU and the heatsink is a common maintenance procedure. This needs to be done if cleaning the dust out of the heatsinks does not solve your problem.
One quick look at the log file and right away I know that you have a poorly engineered Dell laptop. Intel created a fantastic thermal throttling method that allows the CPU to run as fast as possible without the CPU temperature ever crossing over into dangerous territory. The Dell engineers did not like this so they created their own thermal throttling scheme that can make using one of their laptops a truly miserable experience. Sound familiar?
Instead of graceful thermal throttling by Intel, Dell has decided that when your CPU gets too hot, they will implement their own power limit based throttling scheme. The turbo power limits are reduced so your CPU with a 45 watt TDP rating is forced to run at less than 10 watts. The CPU must slow down to approximately 800 MHz to keep power consumption as low as possible. It seems to get stuck at this speed for 30 second periods at a time. This is when your frame rates hit the toilet and your computer becomes unusable.
The MULTI column is the log file represents the CPU multiplier which represents the CPU speed. The far right column in the log file shows the reason for throttling. You will see PL1 power limit throttling as the reason and the multiplier (8.00) in the MULTI column is being forced down to its minimum so the CPU runs as slow as possible. There is no logical reason for a throttling scheme that is so excessive. No other manufacturer does this. Only Dell.
Dell introduced this power limit based extreme throttling scheme when their laptops with Intel 7th and 8th Gen processors were released. This new and improved throttling method often times cannot be fixed by using ThrottleStop.
To try to fix your problem, improve your cooling and do whatever it takes so your CPU never goes over 90°C. Anytime it is allowed to hit 100°C, this seems to trigger the extreme power limit throttling scheme that Dell is using. You might be forced to use some ThrottleStop features like Disable Turbo to help keep the temperature down. If you choose to deliberately run your CPU at a slower speed, that might be better than Dell randomly deciding to run your CPU at its slowest possible speed.
In the TPL window check the MMIO Lock box and also check the Speed Shift box. Post some screenshots of ThrottleStop if you need some more suggestions.