I don't know what caused this to stop working for me. That doesn't matter, so I want to press function keys on my bluetooth keyboard and avoid using the FN key. Here is what I have tried.
I went into System references > Keyboard and I can see that the checkbox is checked that allows the function keys to work like I want, but I found out that this is not for my bluetooth keyboard. I checked this by trying both keyboard's function keys after turning the checkbox off.
After this, I told my Mac to search for the bluetooth keyboard, and even though it was paired, it said it couldn't find it. I went into Bluetooth settings, unpaired it and paired it back up. Then I went back into keyboard and defined the keyboard by following the instructions there.
Next I googled and found out that there is a piece of software from Logitek that is supposed to be able to change settings. for various devices, including my keyboard. I downloaded it and found that many of the buttons have bad accessibility messages or none at all. I kept pushing buttons and hoping I would get the right settings to pop up, but haven't been able to get that to happen.
So if anyone has a way to reverse the function key behavior on the K375/80 keyboard, I'd greatly appreciate it if you would point me in the reverse of the direction I'm going now.