Native Boot install won't start after moving disk (external USB to internal SATA)

OK, this is my last post in this thread, because I just can't get my points across. I really do appreciate all the help/suggestions, but this is NOT a bootloader problem. If I make any changes to my BIOS, regardless of what they are, I can get my internal SSD-based Linux and Windows Native Boot systems to load. After the next cold/hard reboot, the disks just disappear. They do exist, of course, after I load any system that's installed on the NVMe or external USB disks; all partitions are available, no disk errors. I've already reloaded/resest both Windows Boot Manager and GRUB, both fail the exact same way: the disks just aren't there.

The only thing I've not tried is removing the NVMe disk and trying to install on one of the internal SSDs. But it's just not worth it.