The difference is difficult and the linked question gives a decent explanation, but here is my two cents:
When you use
料理するのが, it immediately feels like there is a direct actor involved. If you look at all the examples sentences in the link, when you use
の, it puts a focus on the fact that somebody is performing the action.
However, when you use
料理することが, the focus is no longer on the actor involved, but the action itself. If I would translate the third sentence into English, it sounds to me like the following:
The act of cooking has become better.
I realize that the above sentence is unnatural English, but my point is that the difference between
こと is whether the focus is on the actor or the action itself.
However, my above explanation might not fit every pattern, so I would take this as general advice. For example,
In the above sentence I am using
こと even though the act of "watching" has a direct actor involved. I believe the reason why
こと sounds better here is because the act of liking is focused on the
サッカーを見ること which is the focus of the sentence.