There are many, many keyboard layouts out there. Maybe it's time for an input standard that acknowledges this fact, instead of endlessly putting the onus on OS developers and users. Maybe keyboards should output UTF8 instead of messy keycodes.

This would require new hardware.

If one is already going to be purchasing new hardware, one may as well get a QMK keyboard. This way you can program it with any keyboard layout you would like, and it will work on any computer without having to change the system defaults.

Clearly this doesn't help with built-in keyboards such as found on laptops; the clear workaround for this specific product is to allow it to import keyboard layouts in the various OS-specific forms they exist in.

Sadly it doesn't seem to work that way. BE/AZERTY keyboards, for instance, have a physical key that US/QWERTY keyboards do not (<>\). The OS will ignore that key unless it's set up to use a layout that includes the key. There is no way to program a QMK keyboard to fix that (unless you change the OS to run the BE layout), because QMK does not map keypresses to characters. It maps keypresses to keycodes, which depend on OS keyboard layouts, specifically US/QWERTY and sometes DVORAK. At least that's how I see it.