undervolting of the CPU core and cache by -0.125mV
That is a rookie mistake. Do some Cinebench testing to get a better understanding of using different core and cache voltages. The 8750H will run better with the core set to a much higher value compared to the cache. Typically the core can be set to -200 mV while the cache is at -125 mV. Here are a couple of examples.
drive.google.com
For the EDP OTHER throttling problem across all three domains, go into the FIVR window and set the core and cache IccMax to the maximum, 255.75. In the TPL window, you also need to set "Power Limit 4" to 0.
Above Power Limit 4, check the Speed Shift option. You have an 8th Gen CPU that is capable of using Speed Shift Technology but your laptop manufacturer did not enable this feature. You need to use ThrottleStop to enable this. When this is checked, press Apply and ThrottleStop will show you the appropriate values for Speed Shift Min and Max. For the 8750H, Min is 8 and Max is 41.
After you press OK and go out to the main screen, you should see
SST in green. Now you can check the Speed Shift - EPP box. Set the EPP value to 0 for full speed all of the time. Set EPP to 80 if you want your CPU to slow down when it is lightly loaded. This is not that necessary when plugged in but some users still prefer doing this. When running on battery power, an EPP setting of 128 or a little higher works well.
Check the MMIO Lock box and clear the Disable Power Limit Control box. Clearing this box tells ThrottleStop that you want ThrottleStop to actively manage your power limits.
I would set Long Power PL1 to 60 and I would set Short Power PL2 to 70. Set the turbo time limit to the default value, 28 seconds. If you have good cooling, these settings will help out with getting maximum performance.
After you do all of that, turn on the Log File option and go do some testing. Run Cinebench or play a game for at least 15 minutes. When finished testing, exit ThrottleStop so it can finalize your log file. Attach a log to your next post so I can see how your computer is running. It will be in the ThrottleStop / Logs folder.