EDIT:
So as @dirkt recommended, I checked the output of evtest, and I get the following lines for Fn+F11 and F4 respectively:
Event: time 1609244073.713496, type 1 (EV_KEY), code 113 (KEY_MUTE), value 1 Event: time 1609244073.713496, -------------- SYN_REPORT ------------ Event: time 1609244073.738779, type 1 (EV_KEY), code 113 (KEY_MUTE), value 0 Event: time 1609244073.738779, -------------- SYN_REPORT ------------ Event: time 1609244076.661538, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e2 Event: time 1609244076.661538, type 1 (EV_KEY), code 113 (KEY_MUTE), value 1 Event: time 1609244076.661538, -------------- SYN_REPORT ------------ Event: time 1609244076.687504, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e2 Event: time 1609244076.687504, type 1 (EV_KEY), code 113 (KEY_MUTE), value 0 Event: time 1609244076.687504, -------------- SYN_REPORT ------------ Both have the same code (113 KEY_MUTE), but I get an extra line Event: time 1609244076.687504, type 4 (EV_MSC), code 4 (MSC_SCAN), value c00e2, when I do not press Fn. The same goes for all the regular keys like letters and numbers. But when I use the F1-F12 in the combination with the Fn key, the line disappears. So my follow up question is, can I make use of that extra line, so that linux distinguishes between keys with the same keycode, and if so, how?