I've left the rig for more than 12 hours. I don't know how you disabled your updates but I can assure you that mine aren't running. The OS is running for more than a year and the build version is 1 year old, that's when I disabled them. I said that I tried with another drive, with another Win10 installation and it's the same.
A reboot doesn't fix the issue for a day or two. This happens 30 to 60 minutes after reboot.
The CPU is more than capable to run Win10. My main PC uses an I7-2600k which is 4 years older and it's running Win10 fine. Lots of new notebooks made in the last 1-2 years, which come with the "Win10 Compatible" logo have slower CPU's than this Celeron. The CPU is not the problem.
Okay, I'm going to recommend installing Windows 10 LTSB version without the internet and then disabling all the options related to updates.
Then connect and install the latest Nvidia driver manually.
At first plug in just one card. If everything goes smooth, then second and go on until all the cards are plugged.
It might be a card malfunctioning or OS related issue.