The DKK5499 is with VAT. If I enter a San Francisco zip code, it still only comes out to about USD654.

Sales tax in the US is nowhere near 25% :)

Yup, Louisianna has the highest combined state and local sales tax rates on average of ~10% which is no where near the VAT standard which seems to be around 20% for most of Europe?

https://taxfoundation.org/data/all/state/sales-tax-rates/