UPDATES: I have now successfully "secure erase+"ed my SSD in the UEFI. I have created a bootable flash drive from windows media creator (or what ever it's called) as opposed to etcher. Now instead of getting "could not find media devices", it's giving be a blue screen. Error 0xc0000185: a blue screen. Both before and after my SSD erase, it says my system needs to be repaired, and I have to plug in installation media (which is what has that message programmed in, so I already do have it plugged in).
Also what I meant by non-adapted TV is its own story. My old Cinema Display used DVI, and the USB-C to DVI adapter didn't work, but the HDMI to DVI did. TVs that use HDMI can connect without an adapter, and might support different inputs or something. That still doesn't explain my monitor suddenly not connecting because it used to.