I had the same problem with my DeBuyer mineral pan. Seasoned it with the potato and salt method. It looked like hell and everything stuck. Then I tried several layers of sunflower oil in the oven. It looked immaculate and shiny. But the first time I cooked in it, the seasoning came off. So I just said to hell with it and kept cooking in it. It still looks like hell but it has become more and more nonstick.
Yes, carbon steel and cast iron benefit from different seasoning methods and oils. Both pans are composed primarily of iron. And Ironically, carbon steel pans actually have slightly more iron. Cast iron pans are more porous, and so benefit from a more saturated/viscous oil like Crisco, lard, avocado oil, etc. The fat/oil sinks in to the pan’s pores more and it is easier to build up coats of seasoning. Carbon steel pans are more polished and smooth, and thus much less porous. Any seasoning tends to sit on the surface where it is more vulnerable to being stripped off. That’s why it’s better to just season carbon steel pans with unsaturated oils and just cook in them. It takes longer to build up any seasoning.
