Hello, I am Meer and I am happy to help you. The problem you are having is probably the device itself. Have you pressed the fn key too hard? It might not look like you have it stuck outside, but it can be stuck inside. Try taking the fn key off. See if the component is damaged. If it is, you will need to replace it.
The problem can also be shortcut key. You might have accidentally pressed a shortcut that changed the hotkeys.
I am not sure if you have Windows 10 or Windows 11, so if I don't know the OS, I cannot help you with the settings.