Add'l BSODs (1909)

It's just wait and see what happens, not much that can be controlled. Use your computer as you normally would.

If you crash again, upload new logs. We'll need new dumps to look into the crash.

If, for any reason, you get into more trouble with crashes, like a boot loop, let me know about it. In the case of a boot crash loop without driver verifier, you can use the same methods described in post #41 to get out of it, but as we're then not looking for methods to disable driver verifier more options become available.

I've been going over this thread a number of times today and only now does it cross my mind.

I have seen these kinds of situations before, unfortunately they usually end up being a very annoying issue. Most of them turn out to be an issue with the motherboard, though it's always difficult to narrow it down to that. Adding up everything you've described and my suggestions it makes me suspect the motherboard.

That's unlikely, although I have opposite experience, BIOS updates usually don't cause problems.

Back in 2016 a short while after I built this pc I started experiencing freezes at random moments that at some point became unbearable. After a lot of troubleshooting I was able to pinpoint it to an issue with the BIOS. It was just a coincidence as I was prepping for an RMA of the motherboard and stumbled upon a few BIOS updates that were released 8 months after the freezes and I decided to give them a try. The updates didn't explicitly state that there was any fix, but sometimes underlying changes can be enough to solve a problem which is what I hoped for and it worked. The reason I suspect the BIOS is because in between building my pc and getting the very first freeze, the last significant change was an update to the latest version of the BIOS and before the update everything was fine. I have created a thread about it here documenting parts of what I have done to resolve it.

The newest BIOS for your board is F9d 5‎.49 MB 2‎018/03/09

Gigabyte Z270X-Ultra Gaming

Download and unzip the file. Run autoexec.bat

Here's the link to my troubleshooting thread if you're interested. It's a bit lenghty I notice.
Random system freezes for weeks