Welp, I was in the middle of watching a movie last night, came back from getting a drink to unpause it, only to find my PC frozen. It restarted, I expected it to boot up like normal, except it didn't. "No bootable device found." Tried a few different solutions and not a single one worked.
Long story short: I had to buy a new SSD, install Windows 10 from scratch, and keep getting a "fatal device hardware error" on the old SSD. I didn't have anything particularly important on there (99% of my stuff is on external drives), but I
did have 10,000+ fonts I'm kind of pissed about losing.

On the plus side, my PC is running way faster with the new drive!
I bought this PC refurbished so I didn't expect much, but I
really should've replaced the SSD back when I put in a PCIe WiFi/Bluetooth card.