How to do heatless curls with rod properly?

I have straight fine hair that is apparently determined to undo every curl I attempt. I got a satin rod after the sock method failed me and my results are better but still not consistent. Some sections hold a wave overnight and come out looking great, others just slip loose by morning and I wake up with half my hair straight. I wrap on almost dry hair, I secure the ends with the scrunchies that came with it, sleep in it, take it out slowly in the morning and wait before separating.

The sections that work look exactly like what I see on tiktok, the ones that don't are completely straight like I never wrapped them at all. I can't figure out what I'm doing differently between sections because it feels the same going in.