Earlier quoted context omitted.
I would imagine that "okej" is more akin to English's "okay".
I can’t really explain why or how and my fellow countrymen could reasonably disagree with me, but „okej” to me has slightly negative/aggressive connotation? Like in an argument I’d type „okej, but you understand why that makes me feel bad”, whereas I _think_ I’d still use „ok” in English in that case? It’s really weird to explore the subtleties of your own language use to that degree, gotta say :P
There is, for example, a divide between “Excuse me” and “Sorry” in English vs. “Bitte” and “Entshuldigung” in German. Cantonese Chinese has two different versions of “thank you”, one that is heartfelt and one that is for an expected service, and using the wrong one is a major faux pas.