What is the ruling on acting roles that involve impersonating God or dealing with Him or mentioning Him, in an academic specialization that includes Greek theater, knowing that the student is excelling and fears failing or not completing their studies if they object?

It is permissible to act, provided it is free from Sharia prohibitions, among which are that the actor does not utter disbelief and does not impersonate a disbeliever. Greater than that is impersonating God. If studying or working will force a person to commit an abominable act, then one must search for another field.