The function keys on my keyboard (cynosa chroma) don't work whenever I press "fn". e.g I can press F2 to change a file's name and it works just fine, but if I press fn + F2 to lower the volume, it doesn't work, and it's the same for the rest of the function keys, they work all just fine until I press fn+ a function key.
Another example is, when I press F1 by itself, it opens my web browser, but if I press fn+F1 it opens the web browser instead of Muting the sound like it used to.

I have a Lenovo Legion, these keys work as expected on my laptop's keyboard but they don't on the USB keyboard.

Function keys are not locked, I have tried using the trouble shooter, re-installing the keyboard, updating the drivers and even change it to another USB port but nothing seems to work.
I've used these keys to skip, pause, play songs but they stopped working all of the sudden, unless I accidentally pressed something that disabled this function?

I've checked the keyboard settings on the synapse app too but everything's intact.

Again, all the keys work just fine, including the functions keys, until I try to use them with the fn key.

Any answer is appreciated.