Both seems to be combined with tanha (thirst)
I don't think they are "both combined with tanha (thirst)".
I think of tanha as always meaning "an unskilful craving" -- especially a craving "to have what you cannot have", or. "to keep (permanently) what you cannot keep".
Whereas a skilful version of that is more likely to be called chanda.
Anyway, the way I understand it is --
- If you're an addict, addicted to something, then perhaps you "crave" it
- Perhaps, after a while of experiencing being an addict, you begin to see the disadvantages (including "unpleasantness" and "suffering") of being an addict -- at that point you might "crave not to be" an addict
- With additional right view and practice and skill, and other supporting factors (including perhaps some "good friends"), you might be able to renounce what you're addicted to -- that, then, might be called a "skilful desire", and not just an "unskilful craving"
- Maybe after you have done that successfully, finished training, then there's no more craving and even no more desire -- see the Brahmana Sutta (SN 51.15) for example
I think I can say from personal experience that there are some things that I used to be accustomed to and attracted to, but which I no longer use, no longer crave (never think about), and no longer even feel averse to if I encounter/contact them -- that if I smell them, for example, it doesn't elicit craving or aversion -- it's just a smell, a recognisable smell -- perhaps that means perception (sañña) without much feeling (vedanā).
Even though I'm not averse to it I still renounce it -- perhaps because I still remember and feel aversion towards being an addict (and don't want to resume using the thing and becoming accustomed and addicted again). I don't think that type of aversion counts as "craving not to be", though -- because, given that I am already not, it's not a craving for something to be other than it is.
Still there are some "states" that I'm averse to -- e.g. social conflict -- and I might avoid situations which might give rise to that -- and, I don't know, perhaps my avoiding such situations isn't always "skilful". I think there's some Buddhist training about not being averse to e.g. social situation (perhaps it's more Mahayana or Vajrayana training though) -- see e.g. Aversion and Mahayana -- but I don't know a lot about that.