It wasn’t the design that made the Volkswagon Beetle innovative - it was that the car was rear-engine’d, and the motor was easy enough to repair that a moderately-competent weekend tinkerer could do it.
Admittedly, both Hans Ledwinka (Tatra Engineer) and Ferdinand Porsche (who formed Volkswagon partly at Hitler’s suggestion) copied a lot of each others’ ideas, but I think it was more a case of they stole from each other than VW stole from Tatra.
