GPT-3 will naively do much worse than DeepL at translation tasks; but may do pretty well (maybe better, though I don’t know that anyone’s rigorously compared them) if you contextualize the question carefully, e.g. make it a fill-in-the-blank line after a bunch of pre-made translation pairs, or even a “resolve this blank in the middle of the story” question with both prefixed and suffixed example translation.

But GPT-3 still hasn’t seen “much” non-English test (they only intentionally feed it mostly-English-language sources for now) so it’s definitely not as good at translation as a GPT-4 that had seen equal amounts of other-language corpus would be.