Anarchism understood as a proper model and not just “chaos” is about horizontal and distributed power structures.

The whole idea is that no single person or group has a monopoly on power. Now if you are asking how do anarchist societies prevent people or groups like that from rising up and forming monopolies of power, there are a bunch of different answers. Ultimately it’s about collective action and proper structure.

If your organization’s rules allow for a single person to rise up and take over, it isn’t formed correctly. It’s like the Fediverse, no one server or person gets to make the rules for all the other servers or developers.

Everything is federated by the choice of the instances and ultimately the users. If they don’t agree with how any instance is being run, they can start their own and run it how they want, federating with who they want assuming it is mutual.

Anybody can fork the project at any time, build it different, start a new instance, run it how they want, etc.

You build into your society, mechanisms that resist monopolies of power. It’s like how your body’s immune system has layers of protection against all kinds of germs.

Another example, in typical small company the structure is top-down with the owner usually being a single person with universal power over all their employees. They can hire and fire whoever they want whenever they want. They can shut down the company or change how any part of it operates whenever they want. Nothing in that company structure protects the employees from abuse by the owner.

There is no magic bullet to protect against everything, just like how your body despite being healthy and strong can still succumb to cancer, infection, poison, etc. That isn’t a reason to just give up on being fit and healthy, because it is about improving your odds and trying to make your life on the average better.