I think that you are in the process of experimenting on yourself. The IPL treatment you are having will be likely disappointing also.
Without photos, it is hard know what composes your darks circle.
These are called allergic shiners but they really have nothing to do with allergies or sinus issues.
The critical issue for the lower eyelids is how thin they are. There are some individuals who have actual extra pigment in the lower eyelid skin, however, this is very unusual. Most of the dark circle is optical. In the cheek there is a thick layer of fat under the skin. Light that passes through the skin strikes the fat and is reflect back into the skin. This does not happen in the lower eyelid. The skin is very thin and there is essentially no fat under the skin. Instead there is a thin flat sheet of muscle. The muscle is red. It absorbs the light that passes through the skin instead of reflecting it back out. The lower eyelid/tear though hollow appears dark relative to the adjacent cheek.
The most effective treatment is fill in the tear through hollow. This changes the optics of the area simply by changing how the soft tissues lie. Restylane is the preferred material for this.