The NAZI design, however, is not true stealth. It used charcoal coatings to “absorb” radar.
True stealth, involves complex geometries along with radar-absorbent coatings, the theories for the former being developed only in the 60s.
IIRC, a Russian engineer published a series of works on the math behind it, and the Soviets, thinking that the research was pointless, allowed for its international publication.
The Nazis were the pioneers of all-wing stealth technology
The Horten Brothers were there first.