Your last screenshot shows the first core hitting a max of 98°C while the last core is only reaching a max of 68°C. Both cores are equally loaded. Does that sound a bit odd to you?
It seems like the heatsink is not sitting square to the CPU and making even contact with all of the cores. Maybe the heatsink was not properly installed. You need to replace the thermal paste. Put a flat edge on your heatsink from corner to corner and from side to side. Have a good look at it to make sure it is actually flat. Hold it up to a window and watch for light shining through under the flat edge.
Your undervolt settings are OK. If you have a Nvidia GPU, there is no need to undervolt the Intel GPU. If you are going to undervolt the Intel GPU, you also need to undervolt the iGPU Unslice. If you only undervolt one of these, it does not do anything.
In the TPL window, check the MMIO Lock box. Set the PP0 Power Limit to 0, press Apply and then clear the check mark out of the PP0 Power Limit box and press OK to save these settings. I prefer to check the Speed Shift box in the TPL window and I like setting Power Limit 4 to a value of 0. These are optional settings. Just my preferences.
ThrottleStop cannot be used to solve the main issue you are having; poor contact between the heatsink and CPU.
