I'm actually in this situation on my property taxes.

In San Francisco there is a 2.5 month window to appeal your property tax assessment. I did that for 2020, and was successful (the hearing was like a year+ later) and they gave me a refund.

I failed to do it for 2021, because I was under the mistaken assumption that they'd they'd also adjust my 2021 assessment after my appeal. They didn't. I guess that's on me?

I just sold that property for a loss and 15% less than my tax assessment, and I'm well past the appeal period for 2021/2022 sales tax year. So I think I'm out of luck. I just over-paid by 15%.