Is it settled though? All we know is that one email is real. What do the other emails contain? Are those emails real? Lots of unverified claims made from one camp, and lots of dodging those claims from the other.
This term doesn't mean anything. It's just a meme. How does one actually "verify" anything? When people use this term they mean "someone I trust (e.g. mainstream media) concurs with this statement".
Even if this email has a legitimate DKIM signature it doesn't mean that someone didn't hack these accounts and send these emails or that v.pozharskyi.ukraine@gmail.com actually belongs to the person it is purported to belong to. It could be that some nation state forged the DKIM signature or that they have operatives within Google that did this on their behalf. We could go on.