I have a keyboard here with a handful of extra keys at the top which do all these functions that the author is showing as Fn functions on their keyboard. Isn't that simply the right option?
Also on laptops: yes, I want to change the brightness regularly, but also I use the function keys in applications that support them. There's already like 100 keys on there! How much do the extra ones cost? I don't buy the cheapest laptops anyway, I'll buy what I think will work the best. No manufacturer offers this option though. Even Framework has only half-height escape and function keys shared with Fn triggers :(