You seem to be at least a little bit interested, I suggest you watch some videos on youtube so you understand it better, the channel Second Thought would be a good place to start.
I’ll try to answer your concerns below:
The current ideology of society is the ideology of its rulling class.
Human nature, if anything is much more about collaboration and collective effort than greed, that’s how it has been for most of human history.
That is to say, we precisely see so much greed everywhere because we live in a system that heavily incentivizes individuality and greed. From the way we are taught to the media we consume, it’s literally everywhere. We are heavily influenced to think and see things in this particular individualistic way.
A society that puts human needs and collective effort above profits have a different way of viewing and interacting with the world than the way we do in capitalist societies. Besides that, if your concern is people abusing power, there should be mechanisms in place to account for that.
My knowledge on this whole topic is not deep, but I guess something you could look up is democratic centralism to understand how hierarchy works in a marxist-leninist socialist state.
Also, my understanding is that marxist theory is only dogmatic in relation to it’s method, as everything else about it adapts to the reality and the material conditions of the time and place it is to be put into practice.