I can create a non trigger PhysicsCollider at runtime using
PhysicsCollider {Value = Unity.Physics.SphereCollider.Create(
new SphereGeometry {
Center = float3.zero,
Radius = 8,
}, CollisionFilter.Default, Material.Default
)});
But I do not know how to make a new physics Material with IsTrigger set.
[edit] my bad it is easy.
new Material{Flags = Material.MaterialFlags.IsTrigger}