Your 2020 return starts out by assuming you didn't get any Stimulus payment so it gives you the full amount. Then near the end you enter how much you actually got so it only gives you the difference if any. You don't get it twice.
Check line 30. The Recovery rebate credit is on 1040 line 30. It either adds to your refund or reduced a tax due.
Before filing, You can preview the 1040 or print the whole return
https://ttlc.intuit.com/community/accessing/help/how-do-i-preview-my-turbotax-online-return-before-f...
