All of that was greatly improved over time. Centrifugal pump was taken by von Braun from fire engines, boundary level cooling wasn't as good as transpirational cooling, and regenerative cooling was with little supports, which required thick and strong fire wall, so they only could use 70% ethanol.

Still - hats off to the pioneers. It's always pretty hard.

I would hope that it would have improved over the last 80 years :-/

The V2 had other foundational inventions - the ballistic missile shape, and the gyroscopic guidance system.

I forgot to add that they also added baffles to prevent pogoing, a technique that persisted at least into the Saturn V engines.