House Sq Footage Issue

[Amit Shetye]

I bought a house during the covid downturn in Dallas TX. The plan we like showed 3200 sq feet. Since I was a first-time home buyer did not know ins and outs of every aspect of home buying. When we did the appraisal the first red flag came which showed the house at 2900 sq ft. But by that time which is July of 2021 during the closing, the prices had already skyrocketed. Builder said it was an error from appraisal and they are used to making such errors. My bad and I believed the builder and moved in.
Now I want to sell my house, so called the county to correct the sq footage. They sent their person to measure the house and guess what it turned out to be 2900 sq ft again. Now the builder is raising his hand and saying he can't help.
My question is:
What is my option now?
The person who did the measurement did not count the stairs in sq footage but said even builders should not count it even if we add that it's just 75-80 sq feet.
At what sq footage should I list my house?
There are 6 houses in my community and all of them show correct 3200 sq ft in county records.