Reality:
A long press engages the capslock function.
A quick press is used to switch languages. So if you’ve set your computer to just 1 language, it’s not going to do anything. If you have more than 1 language, it switches between them immediately. There is no delay.
Apple fanbois… Apple is using AI magic to know when I want to press it.
https://stackoverflow.com/questions/77002505/command-to-change-the-value-of-use-the-caps-lock-key-to-switch-to-and-from-u-s
Though the guy is talking about something else; it was the best screenshot that showed where the setting is.
For me, pressing just the fn key does nothing and even mine has the symbol. “fn+space” just puts a space. I can easily switch languages using the capslock. If I do a slightly longer press; the capslock turns on.