What's the coolest solution for the Ryzen 3900x?

I have a Corsair H150i pro with 3 120mm fans capable of 6k rpms but I keep them at 2500.
At the moment I'm using Arctic Frost thermal paste.
My Air flow is Top/Bottom Intake Front/back Exhaust
Gaming it will get to 70-80c
Idle sits around 42c
Browsing web pages, watching movies, general use it averages 55c.
Cinebench rockets it straight to 92c and can't finish the test.
The overclock used to be at 4.75ghz but after the BIOS update I can't remember what I did to get it that high so it's at 4.47ghz. All I did was adjust the CPU ratio and disable AMD Cool 'n' Quiet.

I was thinking a thermal pad or Thermal Grizzly Hydronaut.

It's stable at 4.5 I just want it to run colder.... I've read undervolting helps but I don't know where I'd set it at my current speed.

Untouched... 1.50v

I took it down to 1.3v and it's already 20c cooler, thank you! This is just general use, I haven't gamed on that voltage yet.

Update; I got the IRQ NOT LESS OR EQUAL during cinebench so I took it to 1.4v. Tried on this voltage and no BSOD but Cinebench threw up an error. BUT I didn't hit 92c, only got up to 70c.

I took the voltage down to 1.35 and ran 3DMark. It ran fine without issue.
Uninstalled Cinebench.
The temps are still way better topping out around 78c in 3DM.

Idle temp is 26-30c
General use is now at 38c

Auto I believe. I haven't touched the DRAM voltages. Dragon center shows 1.3600 v
I noticed the sticks are 3600mhz but an untouched bios had them at 2800ish.
If I try to go any higher the BIOS says that OC setting failed.