Realbench overheating cpu

[Cannon.19]

I'm still testing my new setup to see how low I can undervolt while stable in prime95, realbench, etc...
My setup:
CPU: i9-10900K
Cooler: bequiet Dark Rock Pro 4 (with both fans installed)
Thermal paste: Thermal Grizzly Kryonaut
GPU: Asus TUF RTX 3080 OC
RAM: 2x16GB 3600MHz HyperX Fury
Motherboard: Asus TUF Z490-PLUS
Case: Asus TUF GT501 (3 intake fans at the front panel, 1 exhaust fan on the back)
BIOS settings:
XMP: XMP I (DDR4-3603 17-21-21-39-1.35V)
ASUS MultiCore Enhancement: Enabled - Remove all limits
SVID Behavior: Auto
AVX Instruction Core Ratio Negative Offset: 0
CPU Core Ratio: Auto
Power-saving & Performance Mode: Auto
CPU Load-line Calibration: Level 4 - Recommended for OC
BCLK Aware Adaptive Voltage: Enabled
CPU Core/Cache Voltage: Manual Mode
CPU Core Voltage Override: 1.370 V
DRAM Voltage: 1.35000 V
CPU Core/Cache Current Limit Max: 255.75 A
Long Duration Package Power Limit: 4095 Watt
Package Power Time Window: 56 Sec
Short Duration Package Power Limit: 4095 Watt
Intel SpeedStep: Enabled
Intel Speed Shift Technology: Enabled
Intel Turbo Boost Max Technology 3.0: Enabled
CPU C-states: Enabled

So the clock frequency right now is 4.9GHz on all cores.
Vcore voltage under load (during realbench stress test) is 1.288v. I'm still not 100% sure if it's stable, but at 1.279v I had WHEA errors in hwinfo. I'll have to test 1.288v some more before I'm ceratin it's stable.
However, I couldn't believe how high the realbench pushes the temperature (it goes to 99C in 5 minutes), especially considering I used to run realbench for 6 hours on my gaming laptop (i7-4720hq|gtx 980m) and temps were never even close to this. I already checked the cooler mounting pressure and thermal paste spread, it was perfectly fine (then I reapplied the thermal paste of course).
I also tested with case side panel off and temperature was only 1C lower than when I tested with side panel on (in blender), so airflow is not an issue either.