let me explain how to use the gizmo option, it was made exactly to remove the saw tooths on the liquid walls.
in the most cases, the liquid is in contact with some geometry. this always lead to saw tooth-like liquid borders (this are just cells), but if the geometry is opaque, you can solve the problem pushing the geometry-liquid interface inside the geometr. the saw tooths still exist, but are hidden. to push the liquid to penetrate the geometry use inscribed voxel mode during the simulation, see the simulation panel. in your case the geometry is invisible and can’t be used to hide the liquid tooths. however, you can cut off them using the same geometry as gizmo. put it in the gizmo slot and check “invert volume” to make the outside part visible