Fn 4 non funziona in OS 15
F 4 non mi da più le applicazioni. Non trovo in Mac support un sistema per configurazioni della tastiera che corrisponda a aiutare. Ill modulo di sotto non prevede Sequoia.
iMac 24″, macOS 15.1
I assume that you are looking for Launchpad - that screen that displays your applications, similar to what you'd see on iPhone and iPad.
Check in System Settings->Keyboard->Keyboard Shortcuts...->Launchpad & Dock
There you can add a keyboard shortcut to Launchpad. Check the box next to "Show Launchpad", then double click where it says "none", and press the key combination you want. You can't use F4 by itself, but Fn+F4 is a good alternative. (Full disclosure: I never used Launchpad, except to answer questions like yours. Pressing Command-space and typing the first few letters of the application is much quicker - just a suggestion you might try)