For one, the reform and opening up of China started with allowing capitalist development in just 4 cities. A sort of test where they could see what worked, what didn’t and then expand the reforms gradually to other places. In the end it was a great success and led to rapid development of the productive forces and quality of life for Chinese people.

What they didn’t do was allow capitalists as a class to take political power, despite the attempts at color revolution during events like the Tiananmen Square protests. Deng and the CPC had a way better grasp of theory than Gorbachev who was basically a dumb SocDem.

There’s this quote from Xi which is important:

Why was the Soviet Union dissolved? Why did the CPSU collapse? One important reason was the struggle in the ideological field. Historical nihilism rejected Soviet Union history, CPSU history, Lenin, and Stalin; it messed up the thinking. As a result, party branches perished; the party could not even control the military. Therefore, a big party like the CPSU was dissipated; a big socialist power like the Soviet Union collapsed. This is a vital historical lesson.

The communists lost control of the military in USSR and Yeltsin/the west was able to weaponize it against them.