The BIOS is at its current version already.
I think I may have inadvertently sent you down a rabbit hole with an unclear comment about display drivers. I wasn't talking about the display driver for my GTX 980; indeed, I updated that to the most current version this past Friday. What I was referring to was the VGA driver from ASUS, which is only used when you're using the CPU's Intel HD Graphics instead of an external graphics card. When you have a GPU plugged into a slot in the motherboard, as I have, the Intel HD Graphics are disabled in the BIOS, don't exist as a device in Device Manager, and therefore cannot have a driver installed -- the install program terminates with an error message that the computer's hardware does not support this. The Intel HD Graphics had never been enabled during the lifespan of this computer, and can only be enabled by a custom toggle in the advanced section of the BIOS which can itself cause further problems when you are using a separate GPU.
I went through all the links you provided. I was originally going to include a step-by-step run-through of all of them, but, while I will do so if you want me to, it really would be a substantial waste of your time, because virtually every link has almost the exact same list of steps (update the device to the current driver, update the chipset drivers, run SFC, reset the BIOS to default), all of which I've already done, usually many times. The only additional suggestions were to "run Windows Update" (which, of course, is what caused this problem in the first place; it only showed up after KB5003637 BSODed my machine and Windows attempted to roll it back) or to "reset the O.S." -- which, as far as I'm concerned, would be my absolute last resort, as trying to reinstall the many different programs I use (some of which are dependent on several others, particularly in my photo and video editing work) would be an absolute nightmare.
I continue to be struck by the fact that this showed up after the failed update. While all of the methods in those links above seem to work from the assumption that it's the device/driver itself that is the problem, the fact is that, in this case, those exact devices and drivers were working perfectly before the failed update and then the automated rollback. I can't help but think that something in the rollback itself didn't work right, and corrupted something that didn't get fixed by the repair install I tried before my last response.
Thanks for continuing to work with me on this. If you want me to include the file where I went through each of the links you provided took notes, I'll be glad to, but I think all it would establish is that, indeed, I actually read them all.