Did Windows 10 Corrupt My APFS Partitions?

Hi everyone, first post here (and on Reddit, too)!

I built a new Hackintosh in the spring, and have been running nicely with Mojave. The build is:

• Gigabyte Z390UD
• Corsair RM650x
• Intel Core i3 9100
• Corsair H55 CPU Cooler
• Crucial Ballistix Sport 2x8GB @ 3200Mhz
• Fenvi FV-HB1200 Wifi/Bluetooth
• Samsung EVO m.2 NVMe 500GB
• Corsair 200R case

I used Clover with SMBIOS 18,1 and used a custom USB DSDT, and a framebuffer patch to get UHD 630 working. Overall, it was a relatively painless build. This week, I acquired a couple final additions:

• Sapphire Pulse RX 580
• Seagate Barracuda 2TB

The RX 580 was up and running after I turned off IGFX in UEFI/BIOS, and finally, I was ready to put Windows on the new HDD so I could do some gaming too!

After fighting with the Windows 10 installer for a couple hours, I finally got it to install, and was able to happily boot back and forth between Mojave on the Samsung SSD, and Windows on the Seagate HDD via Clover, once for each OS. Awesome! (Although Windows seemed to have placed itself first in the boot order in my BIOS, which greeted me with a blue screen of death before I launched it successfully from Clover.)

At this point, something bad happened. I was running Gigabyte's installers for all my motherboard's drivers in Windows, and got to the Intel Optane one. (I'm not even sure if I have any hardware that can take advantage of it, but I figured I'd at least install the drivers.) It prompted me that I would have to format "Drive E:" to continue, so I clicked on Cancel, figuring that was the Samsung. By now, my Radeon drivers had finished installing and prompted me for a reboot, so I said yes.

Long story long, after manually selecting Clover, it greeted me with a single Windows partition and nothing else. Booting from my Mojave Installer USB, Disk Utility shows me three internal partitions, Windows, AppleAPFSMedia and APFS Physical Store. (This is my first time using APFS, so I'm not sure what should be listed in the MacOS Installer version of Disk Utility.) If I run `diskutil apfs list`, it prints out a message which includes 'container error 69808'. I'm currently running First Aid on "APFS Physical Store", and have the spinning beach ball of death, but my tower's HDD light is strobing. I'm not sure what's happening at this point.

I haven't been able to find much on this error message, so I'm pretty much resigned to my Mojave partition being nuked. (Most of the questions I've found are related to encrypted APFS drives, but mine is unencrypted.) Thankfully, after years of hackintoshing, I've learned to only keep application files on the system partition and everything else on an external, so I've only lost a day's worth of work that was sitting on my desktop. I'd greatly appreciate any advice if it is recoverable, though!

My main question is, does anyone know what caused this to happen, or has anyone encountered it before? Did Windows somehow try to write a new bootloader to the SSD after my first "restart" back into it, corrupting the SSD's partition tables? Did the Gigabyte Optane driver do it, even though I told it to not format whatever drive it was trying to write to? (Presumably the m.2 SSD?) If it was Windows, how do I prevent this in the future? I have no way to turn off the m.2 in BIOS, so is there a way to block Windows from accessing it in the OS? etc, etc, etc!

Thanks for sticking with me this far, I'm looking forward into gaining some insight, as this is the first time I've done a dual-boot that wasn't on genuine Apple hardware, and feel like I have a lot of unanswered questions about best practices!

edit: I forgot to mention, the SSD is prefixed with "UEFI OS (Samsung 970 EVO)" in BIOS now, where I'm pretty sure it used to just say "Samsung 970 EVO", which is another thing that leads me to believe Windows is the culprit