The 638 acres (2.58 km2) of land [We Build the Wall] built on is part of farmland that belongs to Neuhaus and Sons, and the wall added over $20 million in taxable land improvement, increasing the tax burden by 75 times. In January 2020, Fisher Industries started a lease-purchase agreement with Neuhaus and Sons for the land under the wall, but had not completed the ownership transfer by their court hearing on December 12, 2020, citing a problematic land survey by Fisher. Fisher’s attorney, Mark Courtois, was hopeful the US government would become owners of both the wall and land. U.S. Customs and Border Protection (CBP) Public Affairs Officer Thomas Gresback said that the wall was privately paid for and on private property, and CBP does not have anything to do with the project. CBP is constructing its RGV-03 project wall outside the floodplain 0.3 miles (0.48 km) away.[66] As of July 2021, the property had been reassessed at 100 times its original value, and Fisher was hoping to sell a 3-mile section of wall (4.8 km) that had cost $30 million to build.[67]
What you quoted says the property was assessed at 100x its original value. The total taxes owed is a different number than the assessed value.
In Texas we have a variety of taxing entities that may overlap a property, city, county, school district, community college district, hospital district, municipal utility districts, etc. Each adopt different tax rates and have defined percentages of valuations they’re allowed to tax. Point being, taxes owed do not scale linearly with assessed property valuations.