I made a scene with many agents
if agents are normal size everything works
but i need them to be big - if I make them big they top moving
and even if i change the navigation region agents settings they still won’t work
Your issue sounds just physics related because navigation pathfinding has no real size, the “agent” is just a point for the navigation mesh in the pathfinding. A giant actor can use the navigation mesh of a tiny actor, it just will clip into walls all the time without a size baked navigation mesh but it stays still usable and moving.
The agent radius is only for the avoidance simulation but not the pathfinding.
You also need to adjust the desired distances on the agent should the size change cause the actor global position to be out of reach of the navigation mesh surface so a different size can still reach the path points. This is again a node setup and collision issue, not pathfinding related as the agent is still just the global position of the parent node unaffected by size.