There was a really good study that covered this topic in part published something like 20 years ago.

It was more widely about how 19th century neo-colonialist ideology and ventures/failures were an important cultural seed in the Nazi ideology on "space and race" and the East and how the remnants of colonialist mentality helped making it more acceptable to the German people. It spoke a lot of the Pan-German League and its forerunners. It also sought to explain why it took roots in Germany instead of in another neo-colonial European power (especially France, just as anti-semite as Germany back then).

I can't recall the title atm, though. It was from German scholars, IRCC. Not very general public, rather one of those big tomes with tons of charts and numbers that are aimed at professional historians or their students, but still rather readable.