Split in tip of nose between cartilage and deviated septum. Would rhinoplasty or fillers be the best option?

I'll get to that in a minute.The split is there because the two cartilages that form the tip of your nose are strong and highly curved, and your skin is relatively thin, so you are able to see the outlines of those two cartilages through the skin. See the short animation that I posted with this answer: the woman had a similar situation, and you can visualize the position and shape of her tip cartilages before surgery.See the "Web reference" link, just below my response. I made a computer morph of your nose, and an animation of the morph, to show the changes that are possible for your nose in truly expert hands.
When the tip cartilages are strong like that, they usually also hold the tip down, so you can see in the morph that I raised your tip up a bit. Then, I lowered the gentle bump on the bridge of your nose.You should understand that the changes I demonstrated in the morph require very advanced techniques, techniques that most plastic surgeons cannot handle. Be sure to read the section in the "Web reference" link on how to stay out of trouble while searching for a rhinoplasty surgeon, and be positive that you followed all the steps, especially seeing before and after photos of other of his patients with wide tips like yours. I can tell you that, at least in the U.S., the great majority of rhinoplasty surgeons would not have a prayer of adequately handling a tip like yours.Your nose is also a good example of why computer imaging is mandatory in rhinoplasty. You need to know exactly what the surgeon is planning to accomplish -- what features he'll change, and by how much he'll change them -- so you know whether it's enough to be meaningful to you, and whether he understands your wishes enough to address all of your priorities. Then, he must show you before and after photos to prove that he can actually accomplish what he draws on the computer.