When properly applied, most users have good success with that paste when used in their laptops. Did you spread a thin layer or did you apply a pea sized blob? For Intel desktop CPUs that use an integrated heat spreader, the pea sized blob works well. When applying direct die to a laptop CPU, I would try spreading a thin layer.
If there is a large difference in temperatures from core to core when all of the cores are equally loaded with something like Cinebench or the TS Bench test, I would look at the thermal paste again. I would also look at the heatsink to make sure it is flat. It can take a few tries before you get good results when applying paste.
The 9750H has a 45W TDP rating and most manufacturers used heatsinks that were good enough for 45W but are not good enough if you unlock the power limits and try to run these CPUs at 60W or 70W. The best paste in the world is not going to solve an inadequate heatsink problem. You might have to reduce your power limits back to 45W or 50W for PL1. Whatever your cooling can manage without overheating. Most laptop CPUs can run reliably at over 90°C so no need to get too worried about the CPU temperature. The CPU will automatically thermal throttle and slow down if it ever needs to.