> bootloader which takes a BIOS file on a USB-Stick and flashes it w/o requiring a working BIOS/Firmware or even a CPU/RAM

For those unaware, this is sometimes called "BIOS recovery" or "crashfree BIOS". In short, if a BIOS update fails and bricks your motherboard, you can load the image of a known-working BIOS update onto a USB memory stick. Normally, a single USB slot on the motherboard has a special marking to indicate that it can be used to "unbrick" the motherboard. Insert the USB memory stick, start the PC, and the BIOS recovery should be automatic. I agree with the parent post: This would be an excellent feature for Framework Computer to add. From a simple Google search, it appears that their desktop computer already has this feature.