They only mean the same when it comes to coming back somewhere.
Volverse is to become. You can only volver the páginas of a book. You can retell something via volver, and also use volver in the sense of 'getting back to' (volver a la normalidad - to return to normal). Volver a + infinitive is to do something again (volver a preguntar - to ask again).
Another confusiong verb is retornar, which is 'turn around', AFAIK.
I think you assumed that "I return" is what DL wanted. I would never say I return by itself. To me it makes no sense in English. I have returned which is one of the past tense, or I will return, which is future, but I return sounds like a literal translation from the sentence in Spanish, which does not make sense in English.
i think that "i am returning" is the form of the present tense that we would use in Am English. Oddly, "I did return" or "I will return" sound fine, but "I return" doesn't. I thought that I should say "Vuelvo a mi casa" and "Regreso el libro", but that doesn't seem to be a real distinction.
You are correct. I asked a 30-something native Spanish speaker in southern California how to say "I'll be back in a minute" (or something similar). He said "Regreso en un momento." That may not be true in every Spanish-speaking culture (Mexico vs. San Salvador vs. Spain), but it's probably understood in most.
Return can have an object and not (I'm not if it is direct or indirect): I return (this is what I currently do). You can say this as you walk into a room. I return it (give back, deliver to original owner). Only valid when in the process of. I returned. (I was at something, left, and then came back) I have returned (I completed the action of returning now, past participle) I had returned (past completed action)
If you say "I did return" that is only valid if you are stating the action happened in response to a question, not that the action is/was happening. i.e. "did you return the book?" "I did return the book." One could even put quotes around "return the book" because it is an action in itself, not a "happening" so to speak.