The problem is that every non-working FN-hotkey gives the same scancode in the logging:
[13688.810924] atkbd.c: Unknown key released (translated set 2, code 0xf5 on isa0060/serio0).
[13688.810939] atkbd.c: Use 'setkeycodes e075 <keycode>' to make it known.
So the solution isn't as simple as mapping a scancode to a key name.
The problem is that every non-working FN-hotkey gives the same scancode in the logging:
[13688.810924] atkbd.c: Unknown key released (translated set 2, code 0xf5 on isa0060/serio0).
[13688.810939] atkbd.c: Use 'setkeycodes e075 <keycode>' to make it known.
So the solution isn't as simple as mapping a scancode to a key name.