Yeah communism is the opposite of decentralization.
All forms of government are.
They are all centralized.
The only difference is that communism pretends to be decentralized in theory.
Real decentralization happens when wealth is distributed more evenly/fairly.
That's all that matters.
You are right, I had in mind the theoretical foundations of the commune. When everything belongs to everyone and at the same time to nobody. Unfortunately, practice has shown that personal interests are not able to exist within the commune.