We all have our strong and weak points, and it feels like the abs are one of these bodyparts some people have amazing despite not working them at all, or the opposite.
For instance, I never do direct abs yet I have deep cuts and they are really visible even when at 18%. I do them like 1 month per year.
My brother on the other hand do them a lot, is leaner than me, yet he has way less abs. They are a bit blurry.
Or maybe it’s another variable to consider: the type of training. I do tons of indirect abs work: deadlifts, squats, carries… whereas my brother barely.