Special Keys and Function Keys on Magic Keyboard Not Working!

My old magic keyboard from 2013 just died recently, so I bought the latest magic keyboard to replace it. I've managed to add it as a bluetooth device and all the keys, except for the special row/function keys work. Anywhere I search says I should check an option that says 'Use F1, F2, etc. as standard function keys’. However, I don't have a box like that to check at all! I've followed instructions from forums and nothing has worked yet. I've removed my keyboard... re-added it... restarted... I can't adjust my brightness, cannot turn up the volume... and holding down the 'fn' key to do anything is also not working! I don't know what's going on. I am on Catalina at the moment. My 2013 keyboard was working just fine and my special keys worked well too.... HELP. This is way too much work for a keyboard!