This is all a bit of fun.
I see what you're getting at... & have reviewed your previous points in this thread, but disagree.
Fedor was born in the USSR... (now known as Russia.) in Rubizhne which was in the (then) "state" of Ukraine. As mentioned, that's on his official birth certificate... & as mentioned by a poster from Russia... they didn't change those designations. So "officially" he is not Ukrainian.
However, if you want to go further...
his family moved out of Ukraine when he was 2 years old to "Stary Oskol" which is a part of today's Russia. (& long before Ukraine became independent.) That's where he grew up. So if where the guy lived his whole life is any indication of his technical nationality... at no time did he ever live in the "independent country of Ukraine."
I'm not sure if you're actually invested in this idea. (not that it really matterz) or just trolling for a laugh... (all good either way) but here we have 2 indicators that he's "truly" Russian. He waz long gone from Ukraine before they became independent & on top of that, the official designation of his citizenship is in fact Russia.
To complicate thingz further, I'm not sure that Rubizhne, (where he waz born) might not become a part of Russia again after this horrendous war... but that's pushing teh discussion a bit further into teh weedz. If it does get turned back over to Russia... would you then consider him Russian?