The maximum amount of syncable objects that can be active is currently ~100. After the max is reached, additional objects are destroyed automatically as they’re created.
These lines are executed in CoherenceMonoBridge (642-644) when this happens:
if (destroyReason == DestroyReason.MaxReached)
{
Logger.Warning($"Max entity count exceeded. {sync.name} [{entityID}] will be destroyed.", ("context", this));
}
It is difficult to create anything of scale with this constraint.