How to map an action to a list of keycodes with xmodmap?

I'm using ubuntu 20.04 on a MSI laptop.

The problem that I found is relative to the keys that can be used with the fn e.g. the key fn+f3 should disable the touchpad.

In the system settings if I try to create a normal custom shortcut and I press f3 it is recognized, but if I press fn+f3 I don't get anything, practically the system is not recognizing it as a key.

I know that I can use xmodmap to change the mapping of keycodes to keys. The problem with that is that if I use the command showkey -s and I press the fn+f3 I get the code 0x1d 0xe0 0x5b 0x76 0x9d 0xe0 0xdb 0xf6 and if I do that without the -s option I get the following output.

keycode  29 press
keycode 125 press
keycode  85 press
keycode  29 release
keycode 125 release
keycode  85 release

I would like to know if there exists a way to map this combo as a command for the system.

If it can be useful this is the output from xev -event keyboard

KeyPress event, serial 28, synthetic NO, window 0x6c00001,
    root 0x296, subw 0x0, time 20618498, (106,394), root:(1848,468),
    state 0x14, keycode 133 (keysym 0xffeb, Super_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyPress event, serial 28, synthetic NO, window 0x6c00001,
    root 0x296, subw 0x0, time 20618499, (106,394), root:(1848,468),
    state 0x54, keycode 93 (keysym 0x0, NoSymbol), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x6c00001,
    root 0x296, subw 0x0, time 20618502, (106,394), root:(1848,468),
    state 0x54, keycode 37 (keysym 0xffe3, Control_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x6c00001,
    root 0x296, subw 0x0, time 20618506, (106,394), root:(1848,468),
    state 0x50, keycode 133 (keysym 0xffeb, Super_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x6c00001,
    root 0x296, subw 0x0, time 20618509, (106,394), root:(1848,468),
    state 0x10, keycode 93 (keysym 0x0, NoSymbol), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False