Get an actual real estate appraisal and see what they price it at. If it’s lower then you can appeal the assessment.
I had two weeks to file my protest and had the hearing before the appraisal review board two weeks later. No time for an appraisal, but my wife is a broker so we pulled several comps from the local MLS.
I was one of a long line of protests they heard that day and we each had five minutes to make our case. They lowered the appraisal from $1.9 million to $1.5 million. They lowered the building appraisal to a little more than it cost to build and the land to $1 million, still four times what they appraised the land for last year.
If I want to protest further I can either sign up for binding arbitration or file suit in district court. I am weighing my options.