yes if you must desire something, it is only to reach nirvana. THe point is that basing your actions, ie thoughts, fantasies, ideas, rationality, ''reason'', talks and acts, on desire (of anything) is a very bad idea, however for puthujjanas it is a very natural behavior and this behavior is what keeps them as puthujjanas.
And of course, the more you care about ''sex, music, entertainment and basically everything else that is or seems important.'', the less you will be successful at stopping caring about those, or more generally about the ''6 senses''.
So on what can you base your actions in order to stop being unhappy, if it is not desire (of anything) or fantasies? Well you base your actions on right view about what you experience, about what is felt. What you experience is typically through the senses and later on it will be about the rupa and arupa jhanas..
So first, you must know ''what happens'', which means you must be ''mindful'' about each of the 6 senses. Once you can keep track of what goes on through the senses, you must apply a filter, you must discriminate between experiences, between what is felt, because it turns out that not all experiences are good, not all experiences are bad.
[Typically, the 6 senses are always bad, the jhanas are always good but still ''anicca'' so you must strive for something else to stop being ''unhappy forever'', which is nirvana.]
There are good actions, good talks and good thoughts, and these good experiences must be cultivated. there are also bad actions, bad talks and bad thoughts and those experiences must be avoided at all cost.
As a puthujjana, you do not know what is good to experience and what is bad to experience [puthujjanas love to believe they are good people and love to believe that they know what is wrong and right, what is worth striving for and what is useless, but they really are just bad people so deluded that they believe to be good people] , so first you have faith in the buddha about what filer to apply in order to stop being unhappy, then you must remember at all times what the buddha said about what is detrimental to your happiness (typically, at the beginning, before the rupa jhanas and the arupa jhanas, it is about the lack of sense restrain), this is called ''sati'', in the meantime, of course you continue to live so it is time to apply the teaching.
Here a sutta about that
This sati is the beginning of the method to ''cool you down'' when you become upset. You notice the bad thoughts and emotions and you remember that acting on the desire or thoughts that you feel when something makes you mad is really a bad idea, so you do not do it. You do not do it, but then you must feel something else than this desire or thought, you must experience something positive, and this is what the buddha did when he had is imagination running wild
Now to catch up with the ''desire to reach nirvana'': the problem with desire (of anything) is that it does not last long, perhaps a few hours or a few days at best, and even worse, as soon as there is something else going in your life, like something big, like some pain, it will become the new focus of your imagination, of your intellect. So if you base your action on desire and imagination, you will train a few days at best and then you will get bored or you will have something else to do and you will stop.
You must base your actions about nirvana on something else, in order to still train for nirvana even when you are tired, hungry, mad about something, completely bored, even when you have something else to do that you love to believe is more important, even when you love to believe that you can defer your progress towards nirvana for a few days, because ''a few days off won't change anything'' like some people say...
So besides desire and imagination, on what can you base your culture of the good actions, good talks and good thoughts and your rejections of bad actions, bad talks and bad thought, even when you do not feel like doing all that ?
THat's when you recall what the buddha said, about how miserable you still are even though, for so many years, you cared about and acted through ''''sex, music, entertainment and basically everything else that is or seems important.'''' and perhaps it is time to do something else in your life, about your faith in the buddha on what is unhappiness and how to stop being unhappy.