It is impossible to give an objective answer here. The beauty of a language is not mathematics. One person hears Spanish and feels energy, temperament, speed, and brightness. Another hears Italian and chooses it for its softness, musicality, and expressiveness.
Spanish is often associated with Latin American music, dancing, travel, sunshine, fast conversations, and lively emotions. It sounds confident and rich. It is especially interesting to listen to different accents: Mexican, Argentinian, Colombian, Spanish.
Italian is perceived differently. It reminds people of opera, art, fashion, beautiful cities, delicious food, and a special lifestyle. It has a lot of intonation, gestures, and melody. Sometimes even an ordinary everyday phrase in Italian sounds expressive.
If you choose only by sound, it is better to simply listen to both languages in real speech. Not educational audio, but interviews, films, blogs, and ordinary conversations. After a few minutes, it usually becomes clear which language resonates more.
But for learning, beauty alone is not enough. It is better to ask yourself: where will I use this language? For Latin America, international communication, travel, and work, Spanish is chosen more often. For Italy, studies, fashion, design, art, gastronomy, or a personal attachment to the country, Italian is the better choice.
Spanish and Italian really are similar, but each has its own character. Spanish is more global and practical. Italian is more intimate, cultural, and musical. And if, over time, you want to learn both, it is completely realistic: after the first Romance language, the second no longer seems so distant.