@hypomodern land value specifically vs total parcel value including improvements? See if Regrid separates them out maybe? https://regrid.com/ (Paging @matth )
Otherwise I think you're writing a scraper for the BS&A website, or making friends with somebody in county government to ask a favor.
if you think scraping out the endpoints of an ArcGIS server is a publicly available database of land values, then yes.
https://github.com/fgregg/horizontal-equity/blob/main/Makefile#L12