I had Linux installed on a tertiary partition of a secondary drive, my F: drive. I neglected to store it within the dedicated SSD, C:, and I believe that GRUB was just not being picked up because instead of being sda or something close to it, it was instead sda6.
First of all sda refers to a physical drive, whereas sda6 refers to a partition on that drive. As for the rest of it, I’m not exactly sure what you are talking about – it doesn’t really matter where in your system Linux is installed; the bootloader probes for an OS, and, once found, will update its table with the position of the OS on the drive.
Further this with the fact that GRUB seemed to not have elevated permissions
This statement doesn’t really make sense; Grub runs independently of Linux (it even loads before initramfs), so the concept of “execution privelege” doesn’t apply. (source)
when I eventually got into its command line, it was not able to run Linux for reasons I’m unaware.
I will point you to this answer, if you wish to boot linux from the Grub command line.
Windows BIOS
There’s no such thing (well, as far as I’m aware, anyways – maybe a microsoft surface, or the like, labels it as such 😜). The BIOS is contained within a physical chip on the device’s motherboard.
Windows BIOS menu never had Linux or any corollary term available as a boot order item
If you’re talking abou the boot menu, it doesn’t necessarily have to list the linux distro. If you know what drive it is installed on, you select that, then the BIOS finds the bootloader from there. A boot device is just that – a device to boot from, not an OS to boot into.
I really did disable Secure Boot. I did so through Shell.
I don’t understand what you mean here. As far as I’m aware, secure boot is only able to be disabled within the BIOS.
I was unsure if maybe there was some alternative command line trickery that exists to modify it that I am unaware of, but a quick websearch seems to corroborate my pre existing belief.
Windows has just been acting screwy as all get out.
This is an unfortunate reality of dual booting with Windows. Windows can do all sorts of trickery on your system (even when the system is powered down!). If I want to boot Windows (I keep it installed on a separate, dedicated, and air-gapped drive), I plug in its drive, and disconnect all other drives related to Linux. This has been the most reliable method that I have found to dual boot Windows. However, this method is still not without possible issue, as Windows can still leave devices in weird states that end up messing with how they are used in Linux.