The concept of democracy came about around that time too (at least the Greek one, which arguably wasn’t the first but I digress)

The Athenian concept of democracy had existed for the better part of a millennium by the time Christianity appeared.

Yes, which is why the USSR never once in its history claimed to have built communism. The best they claimed was “developed socialism” with promises to build Communism someday

People get these confused a lot, but russia has 2 coups in the 90s-

1991 was a failed anti-reformist “left wing” coup that deposed Gorbachev and ended with the fall of the USSR and Yeltsin in power.

1993 was a successful right wing self-coup that allowed Yeltsin to fully consolidate power away from the Russian parliament and towards the presidency. More hamfisted and violent, but in essence similar to what is happening in the US right now