i'm not sure if you're the right person to ask this but does victor speak with a russian accent in the sub?
If by “sub” you mean the original anime voiced by the Japanese voice actors, no, he doesn’t have a Russian accent. He speaks in an absolutely normal standard Japanese! There are a few exceptions where he pronounces English words with a “foreign” accent (like when he says “amazing!”), though they are mostly single words and it happens in humorous/comedy situations. Also, for Russian words like “vkusno” I think he paid attention to pronounce them correctly.
In Japanese anime, “foreign” accents are mostly used for characters like the “token gaijin”, often in an over-the-top way, and are normally associated with humorous situations or characters that cannot speak fluent Japanese (but in this case it’s often minor characters who only appear for a short while), so you wouldn’t really see important characters speaking with a foreign accent in a “serious” context. The most used is probably the “American-like” accent, but they have a “Chinese” accent where too Chinese characters also speak with “-aru” at the end of their lines.
Because of these reasons, if Victor (or any other character) were to speak with a foreign accent people would probably be distracted by it and would find it hard to concentrate on what he says seriously. In YOI no one consistently speaks with a foreign accent, though Michele for some reason speaks in a light and quite stereotyped Hiroshima dialect and I’m still puzzled about that… (Sara doesn’t, by the way). But that still works because Japanese dialects are sometimes used to “color-code” characters.