They are deeply conservative. The more conservative one gets, the more fascist one gets.

AFD didn’t just suddenly abandon their conservative ideologies as they became more nationalist. Their conservatism is baked into their core ideology. Even they will tell you they are conservative. They are on the completely opposite end of the spectrum from progressives.

Conservatism is the very foundation upon which fascism is built. Conservatism is a spectrum. This is how they can convince some moderate conservatives to vote for them. They share the same values; they just lean further to the right than moderate conservatives on some issues.