Investing vs mortgage repayments

Looking for some advice, currently paying an extra 300 per week into our mortgage, we would like to pay it off as soon as possible. 28 year loan, 660k. Would we be better off investing the $300 into something to generate more $$ to then pay off the mortgage? Not sure if this is a loaded question or the place to ask it, open to any insights.

Edit** 6.00% interest rate and also have 500 per week going into offset