Try machine translation not general LLM based ones. Google translate does use an LLM, Gemini, now for translation, but it preserves the nuances of your own speech instead of injecting the clear markers of LLMs like you'd get if you tried to do it via Gemini or ChatGPT directly.
So, write your replies in your native language then post them into Google translate, I guarantee it'll sound better and people won't think it's an LLM.
TLDR yes it now uses Gemini which actually understands idioms etc over the previous Google translate. More importantly, it doesn't rewrite your text to sound more like AI which you see on this thread already with OP using ChatGPT to translate. Works for any language.
So, write your replies in your native language then post them into Google translate, I guarantee it'll sound better and people won't think it's an LLM.