If you have no IHS you certainly should be using liquid metal otherwise there is zero point and you will have close to or worse temps than stock.
Whats happening is your die is convex and there is portions of the die not touching the block. When you use LM this issue is not as significant. Rotate the block and see if you get better temps however i suspect you will not.
At this point you need to use some conducatnaut on the die and the block. Your bios settings are trying to compensate for a poor thermal bond which is not ideal. Also just set Adaptage voltage with no offset or a static voltage.
TJmax will not protect your cpu from degredation when you are pulling 400 watts through it at such high temps and voltages which huge temp discrepancy's across the die. pull the voltages and clocks back until you get the thermal solution sorted as you do not want to degrade your now out out of warranty chip.