Sapphire Vortex Issue with Masking?

Hey guys so I have the following image:

I am trying to make this NON TILEABLE, I just want it to be on the center on the screen, but without the CUTS on the right and left side, I altered the colors so you can see the contrast I am talking about (you can see the sharp cutted edges on right side and left side).

I tried Precomposing then adding a mask, but without success! I just want the vortex edges to be softer, so it fades out slowly if that makes sense?

Below is the tree of FX of the layer in case it is important for this type of thing:
image

Anybody have an idea on how to fix this? Any guidance? Thanks in advance!