My point is, his English has the quality of someone
who has spent significant time in an English language country.

Or, someone who has been speaking in English often.
(Probably Americans as that's what he sounds like.)

Who has Zelinsky been hanging around that speaks 'American'?

Maybe folks from the Obama/Biden team?
(State Dept. - CIA)

Really, listen to his English.

I've heard many, many foreigners speak English.

You DO NOT gain that level of proficiency without being
immersed in that particular language.

It's the little things that I notice.
That makes me an incredible judge of character!