It is not heavy enough. The heatsink is not big enough to dissipate all of the heat a 10750H can create.
You have had the same overheating problem for over 2 years now. I do not know of any magic tricks that are going to fix this. Your 10750H runs hot, perhaps hotter than the average 10750H. You are already undervolting so there is nothing else you can do about that. It still comes down to a heatsink and fan that are struggling to dissipate 45W of heat when a 10750H needs 60W, 70W or 80W to achieve maximum performance. There is no simple fix for that poor design problem.