I don't think there is such requirements: https://www.workindenmark.dk https://www.nyidanmark.dk/en-us/coming_to_dk/work/work.htm

But: - tech salaries aren't US competitive - people often speak Danish (sometimes it's a requirement)

And while you'll probably do fine with English in Denmark in general. Long term you would need to learn the language. And to be fair, it's a useless language, there is only 5M speakers, why would anyone spend time learning that? :)

And yes, you would experience racism too. Just because it's a borderline social-libertarian paradise doesn't mean all the people are angels.