Thank you for the suggestions. Seems like I forgot to reply to this.
Those were the last tests I tried before sending it back to the retailer for a repair/replacement and unfortunately, still getting the same WHEA-Logger events. Due to not getting any BSODs, trying every forum/guide to force enable it, all I can get are the WHEA-Logger events.
It's been two weeks since I last heard from the retailer though even after I send them an email every 3rd day - as they requested that much due to the current situation.
Sadly, I was unable to find the solution since early December. Eventually just sent it to the retailer to see if they can fix it as they test it themselves before proceeding with a replacement. Sorry I couldn't have helped any more. You can try the same tests I've done - to rule any specific parts. I could be wrong, but I would assume the following based on my own testing and other forum posts so far:
I am still concluding - for my case anyway - that it's either a faulty CPU or some sort of communication error between my CPU and GPU models based on all the testing I've done.
For point 1, never seen this before (Win+Ctrl+Shift+B). Guess I have been lucky that I always get crash to desktop or had to do forced shutdowns when I get computer freezes or game freezes - lucky is a bad choice of word since any crash or freezing is not good at all. Sadly, not sure how it will help with my issue as I don't get a choice what to do when I get a black screen followed by a restart. Like mentioned before: black screen, sound continues briefly (in-game and people on discord talking), then the system restarts itself - I don't hard reset/shutdown or do anything to make a restart the computer does it.
Whoever doesn't know point 2 after using a computer over 2 decades, either are lucky with computers and has never experienced the computer freezes where the only choice is a forced shut down. I envy them.
For point 3, I've never had power saving mode on for any computer for over a decade.
However, thank you for the suggestion.
I don't know German, so I used Google translate :p Unfortunately, I have already tried what you have suggested and didn't work for me :(
Thank you for the replies everyone.
Hopefully the retailer can resolve my issue as my motherboard and CPU are with them now. Corsair has my CPU cooler and is taking as long as expected based on reviewers of the product of any Corsair related thing. AMD Technical Help team has been, let's put this lightly, disappointing compared to some of the people on the forum.
Got an update from my retailer and a replacement CPU and motherboard are being sent back to me :D
On their side of testing, both the CPU and motherboard had when tested individually as stability issues - so probably had faulty items to begin with and got worse over time - less than 6 months.
Once I get my CPU cooler back from Corsair (whenever that will be), I can finally test my build again and hopefully there's no more issues.
I'll update this post when I get everything setup and tested for at least a week.
So based on the retailer, current conclusion is faulty/unstable motherboard and CPU - but will confirm this much later. My estimate is mid-March.