дебил тут кто-то другой...

This isn't a sentence. It's an exclamation: "You great big idiot. Why didn't you think I'd like your gift? It's beautiful!" [for example]

This isn't a sentence. It's an exclamation: "You great big idiot.

In this case I expect a comma after you - in both English and Russian
Ты, идиот,...

It can be a period or an exclamation mark, depending on how long a pause the writer wants the reader to make after it: https://www.google.com/books/edition/Emily_s_Lost_and_Found/SaHTAQAAQBAJ?hl=en&gbpv=1&dq=%22You+big+dummy.%22&pg=PT133&printsec=frontcover See two instances here — one with an exclamation mark and one with a period.

…and then one with a comma = shorter pause

I meant some punctuation mark after YOU. Don't know about English, but in Russian it changes the meaning.
Ты идиот! = You are an idiot!
Ты, идиот! Прекрати орать = You, idiot! Stop shouting

If it's the latter, then a comma is needed in all 'translations' of our new troll. However, only the second one makes some sense with a comma added.

In English, we don’t need the comma because we don’t make a pause. We say “you idiot!“

 In other words, the English is correct! Translate it into Russian any way you like.))

The reason you don’t use acomma there is because “you“ in that context is a specifier — in the same class as an article: you Russians, we Americans, that idiot, you idiots, etc. No comma.  only “you“ and “we“ can be specifiers. The pronoun I can’t be a specifier, so it requires a comma: I, Grumbler, am Russian.

OK, thanks.

👍🏼🤩

Believe it or not, this speaker is probably not insulting the listener here, if anything, they were accusing them of being silly. I would go as far as to translate this as Какой же ты глупый!)) 

Well, sounds good. Add it.

Thanks, will do.

My fear is that by leaving your edited translation up, with four stars so far, you’re telling learners that the original is incorrect.

OK, deleted, no problem.

1. чукча не читатель, однако
2. нужна
3. это и есть обращение