Linear support will be added if the overhang angle of the 3D model is larger than the angle you set.
2. Pillar Size
If you want the linear support to have a higher density, you should set a smaller value.
This is to decide the vertical space between the 3D model and the linear support. Bigger value means it will be easier to remove the linear support.
This is similar to the Pillar Size settings space between adjacent support path, small path space will have a higher density of the linear support.