I use the function keys regularly:

• For programming
• For gaming
• For general functions when interacting with the desktop (continued)

Having once seen an infographic of F# key allocations, I considered it neat and it stayed in my memory, so I started using them in a similar way:

• F1 help - thankfully, most programs implement that by default
• F2 rename
• F3 for either a search bar or split viewspace
• F4: don’t remember what was in the infographic, but apart from Alt + F4, I use it to open the embedded terminal wherever available. Other combinations using F4 are used to open the terminal in different ways
• F5 refresh. I recently saw a bug report with a workaround that made me feel like KWin might actually benefit from F5 to force redraw all windows and the whole screen
• F6: similar and complementary functionality to Tab for using keyboard focus.
• F7, F8, F9: alright, not only did I forget what was shown in the infographic but also didn’t find much use of these (I do use them for gaming though)
• F10 for “New …” menu as in New folder/file
• F11 Fullscreen
• F12 different things in different cases, but usually view related stuff. Sometimes an alternative print screen function

I have been trying to select and procure components to build my own keyboard and if I ever do, I’ll be adding the F13 - F24.

But of course, I’m not very into splits and I go with the full 104 keys thingy

I will answer with a simple question: When’s the last time you had to press a function key and a number key at the same time?

When it comes to split keyboards and other kinds of shaped keyboards, smaller is usually better to a point. Standard keyboards are usually more fixed in place and as such, the size doesn’t matter as much as long as you can still reasonably use it.