The system Hot Key API only supports modifiers independent of left/right.
Keyboard Maestro can detect the left/right modifiers with the USB Device Key trigger.
BTT has a different philosophy to Keyboard Maestro, which allows it to do things Keyboard Maestro wont do, because with Keyboard Maestro I restrict it to public APIs used as Apple defines them. This means Keyboard Maestro cannot do something, but it also is why Keyboard Maestro versions all the way back to version 4.x released over a decade ago works on modern macOS Ventura.