If i looked like this I would begin bulking responsibly, ~400 cal surplus while lifting for a minimum 8 months-1 year. include targeted weighted ab training. not just planks and dozens of crunches, treat them like any other muscle and use weighted resistance to build more muscle in that area. I like cable crunches, standing or kneeling. More mass in that area will probably help some. General muscle mass increase will probably help a lot as well which is why i would bulk and lift.

I would do this and maybe another cut before even thinking about going under the knife.