Asus x570 prime pro strange behaviour. Stable overclocked, unstable at normal speed!

Hi,
I'm using the following configuration:
Mobo: Asus Prime x570-pro/csm
Processor: Ryzen 3700x
Ram: 8gb x4 Corsair Vengeance 3000Mhz
PSU: Corsair RM650x
GPU: Zotac nVidia 1060 6gb
WD blue nvme

On default settings in BIOS, my computer keeps crashing, Windows keep BSODing with random error codes every 10 - 15 mins. Linux keeps freezing with last 1 second of whatever audio was playing repeating.
One would expect that default settings work "out of the box".
However, setting the following options in BIOS does wonders and make the pc super stable:
Ai overclock: from (auto) to (D.O.C.P.)
TPU: from (keep current settings) to (TPU 1)
Using these settings since 2 days, and computer hasn't crashed it yet.
Going back to previous settings starts the problem again.

The problem with these settings is that they make the CPU run at 4050 Mhz. I'm not a fan of overclocking, even though the box cooler doesn't let the cpu get above 75 celcius at those settings.

Please suggest me what to do, asus guys just gave me troubleshooting steps and service center phone number. This is my main machine, and I cannot afford to loose however many weeks they take to RMA unless absolutely necessary. Is this normal behaviour? Is it because my RAM is 3000 MHz? The sticker on ram says 1.35v but (Ai overclock: auto) runs it at 1.2v.

Here are some troubleshooting steps I've done to narrow the problem down to those bios modifications:
Tried different RAM, tried all RAM sticks one by one in 1 2 4 config.
Tried different nvme
Tried different GPU (an old amd r7 260)
Tried multiple Operating systems: Windows 8, 10 11, Linux: Ubuntu, Pop_OS, Manjaro, OpenSUSE, Arch etc. Linux is more stable, it crashes only once or twice a day, windows was highly unstable, would crash every 10 - 15 mins no matter the version.
Replaced my PSU in the past.