Yes, there are neo-Nazis in the Ukrainian military. There's neo-Nazis in the American military too, and the German military despite their extensive anti-Nazi efforts, along with neo-Nazis in the Russian military such as the Wagner group. Turns out militaristic authoritarians are attracted to military service wherever they are. I'm not saying that neo-Nazis in the military aren't a problem, but it's a problem like covid in the military is: something that's nigh inevitable as long as it exists, and something to be stamped out when evidence of its existence is found, regardless of which military it's in.