The penalty on an excess contribution is the %6 excise tax.
When entering into 2021 TurboTax an excess HSA contribution made for 2021 and returned in 2022, when TurboTax tells you that you have made an excess contribution and asks how much of the excess you will ask to be returned, that's all you enter. You don't need to know the investment gain or loss at this point, TurboTax isn't asking for that here.
If you've received a Form 1099-SA reporting the return of the excess contribution, code 2 in box 3, box 2 will be the difference between the amount of excess contribution that you requested be returned and the amount distributed, but not less than zero. If box 2 shows a positive number, upon entering that Form 1099-SA into TurboTax will include the box 2 amount on Schedule 1 line 8e. If box 2 contains a zero or is blank, the form is indicating that there was no gain or that there was a loss.
