From other comments, it's just a distinction between "duration" and "instant". Nothing deep, exists in lots of languages. If you want to get the joy of Greek philosophy, you're going to need the philosophy. It isn't just magically included in the language.
From the opening:
"Kairos (Ancient Greek: καιρός) is an Ancient Greek word meaning the right, critical, or opportune moment.[1] The ancient Greeks had two words for time: chronos (χρόνος) and kairos. The former refers to chronological or sequential time, while the latter signifies a proper or opportune time for action. While chronos is quantitative, kairos has a qualitative, permanent nature."
Whereas actually, from Greek speakers here, the difference is that chronos is when you say "it's taking a long time", and kairos is when you say "it's time for lunch". All that "proper or opportune time for action"? "Qualitative, permanent nature"? That is a very specialized usage, mostly used in foreign languages.
The same holds for other "loaded" ancient Greek words.
I wonder what you'd say about λόγος.
One can argue that Christian teology is older than modern Greek, therefore gravity of Logos is stronger than anywhere else