It seems to me that FOSS projects like Linux have a "positive non-toxic" hierarchy. The hierarchy there is only based on merit and imposes no power constraints

It seems to me that FOSS projects like Linux have a "positive non-toxic" hierarchy. The hierarchy there is only based on merit and imposes no power constraints over the members, who all have the same access to the source. If you disagree with the elders, you can fork. I think if your project or team needs hierarchy for the decision-making, then the hierarchical order should have no power (for example, the leaders could be voted in democratically), because that way you get the positive effects and avoid the negative effects.