I’m still confused how Tom Artyom Alexandrovich is his full name. As it’s used in articles and on wiki, Tom is his name, Artyom is ??? and Alexandrovich is supposedly a surname. For my ear it is a mess, see why below, but do know that’s only a theory.

Between eastern slav nations (a lot of israeli immigrants came from here, from USSR and after), Alexandrovich is a popular patronim (son of Alexander), Artyom is a name, and Tom could be a short-hand for Artyom and\or nickname and\or the englification of his name on documents, - and by this logic there’s no surname.

I don’t see how it came to be, but what I know - is (ex) soviet people, especially in official context, used to call each other by name+patronim, e.g. Artyom Alexandrovich, and as a cybersec guy and an arrested pedophile who wanted to keep a low profile (and kept for some time?), he could’ve tried to avoid disclosing his real surname. Probably a sound tactic for someone like him, but other than that, his surname could lead to other interesting discoveries.