No matter what system you have, the luck of the draw will give some people more powerful hands than others. If that is enough to destroy your system, then your system can never be implemented in reality.

The self-managing community would have inequality, but its organisatory principles would address that inequality in the same way that they would address an inequality that is caused by natural randomness. If that method of addressing inequality is more empowering for the community than capitalist democracy, then the community would gain in power relative to capitalist communities. This inspires other communities to likewise empower themselves, and either together or alone they can fight off police action and start a revolution.