Do my desires prove what is good for me?
No. Desire tells you what you want, not automatically what is good for you. A desire is a real fact about your mental state. It should be understood, not obeyed blindly.
A want can reflect a genuine need. You may want sleep because your body needs recovery. You may want connection because relationships are a real human value. You may want food because you are underfed. In that sense, desire can point toward legitimate values.
But a desire can also point toward avoidance, impulse, fear, status-seeking, or short-term relief. You may want a third drink because you are avoiding stress. You may want praise because you value excellence, or because you are attempting to outsource self-esteem. You may want to skip a workout because you need rest, or because you are rationalizing discomfort. The desire is real either way; its meaning has to be judged.
Wanting something at least suggests that you value it in the professed or felt sense. Whether it is actually good for you is a separate question. Whether you consistently act to gain or keep it is another question: Your behavior reveals your operative priorities (what economists call "revealed preference"). If you say you value health, but repeatedly trade sleep, training, and nutrition for late-night doomscrolling, your stated values and revealed values are out of alignment.
Treat desire as data. Ask what it is aimed at, what need or value it may reflect, what it costs, and whether it fits your long-range value hierarchy. Reason should interpret desire, not pretend it does not exist.