See, As the new dates for JEE Main exam are announced to be 01-07 Sep, 2020. So, if estimating the shortest possible time, it may take at least 10-12 days for the evaluation process, i.e., releasing of answer key, raising any error in the answer key, etc.. So, if everything goes fine, you may expect the final results to be announced around 18 Sep, 2020.

Hope this helps.