In the Netherlands, which unlike Germany was significantly involved in the transatlantic slave trade, AFAIK the word meester never had any connotations of slavery, only of expertise and teaching ability (as in a guild master).
It's still used to refer to a male teacher, particularly in elementary schools, as well as being the title used by lawyers.
Or slavendrijver, which is still a very derogatory way to point out exploitative behavior.
I think an important difference between ex-colonial European powers and the US is that the (ethnic) slavery did not take place on European soil. Most colonies were operated with very few Europeans to oversee, and as such people were not as exposed to it as people in the US, where masters and slaves would perhaps not live in the same part of town, but also not a continent away. So this may explain why those terms seem inoffensive/only have their meaning outside of the slavery context in Europe.
It's still used to refer to a male teacher, particularly in elementary schools, as well as being the title used by lawyers.
A slave owner was simply a slavenhouder.