oh of course. I was simple saying if you have a very good grasp of the English language then you don’t need a TEFL. TBH it all boils down to if the student likes you. 80% of people looking for tutoring are looking to improve their conversational English anyway, so there is no need to be an expert with punctuation.
I have tutored many people in the past, mainly Polish, and it’s not hard. You just talk to them and correct them when they make a mistake and explain why we don’t say that certain thing that way.
If you want to learn to be good enough to teach conversational English online then I don’t think a TEFL will help either, firstly it’s a lot about your personality and secondly you’re better off just researching yourself.