I received stimulus check and I cashed it. However, I want to return that money to IRS. Can I do it though turbotax while filing the tax returns in June, 2021?

No, you would need to mail a check to the IRS.  The tax return has a method to claim the credit if you did not receive a payment, there is nothing on the form about returning a payment.

Go to this IRS website for how to return the payment that you cashed - https://www.irs.gov/newsroom/economic-impact-payment-information-center-topic-i-returning-the-economic-impact-payment