I noticed that on many laptops, including the MacBook, function keys (brightness level of the display, volume, etc.) can be used as standard without the fn (function) key. And the keys themselves from F1 to F12 have to be used with the fn key (it is located in the lower left corner of the keyboard).
So that the keys from F1 to F12 work as usual, and the functional only with the fn key – open “System settings” – “Keyboard“, then in the tab “Keyboard” select “Use the F1, F2 and other function keys as standard“.
See also my article:
Fn function keys on a laptop work the other way around