I don't have time to get into all the details of the stupid Gemini and other "re-entry" missions you mentioned. They were nonsense examples of high-altitude rockets utilizing retro-rockets or other techniques to come back down on a planet with a thick atmosphere, and had nothing to do with high-speed re-entries from outer space.

The only thing I may grant you along those lines are the missions to Venus, where the Soviets dropped something down that lasted for a few minutes, and that only worked:

a) because it was tiny and very light, and
b) because Venus has a very very dense atmosphere.