By the time my cast iron cools, I’ve left the kitchen, so tbh i generally clean it before the next time i cook with it, and have never had rust issues no matter what i cooked in it last. Every once in a while i notice the seasoning getting a little thin after scrubbing it, so I reseason it with a single layer on the stove.
With my carbon steel wok, i regularly clean it by tossing it on the wok burner at full blast until it’s entirely red hot and everything has carbonized off of it, and maybe splash some water in to help clear that off. Then i wait for it to cool enough and reseason it with a quick wipe of oil while it’s still hot enough for the remaining heat to polymerize the oil.
Basically, I’ve never spent significant effort taking care of my cast iron of carbon steel cookware, and it’s all still perfectly functional and non-stick and not rusted.
That’s fair. I don’t mean to invalidate your personal experience with cast iron rusting, but I do want to present a counter experience so people don’t think it’s definitely like that.