It depends. Performance-wise, the 5-star upgrades usually produce a similar gain to C1.  On one hand, Polar Star, Aqua Simulacra, The First Great Magic are more broadly useful across Ganyu’s different teams. Their unconditional nature makes them a huge QoL improvement over Prototype Crescent and Hamayumi, and they look fantastic on Ganyu.  On the other hand, C1 is cheaper and lowers ER requirements so you have your Burst up more often. If you want to do solo runs, C1 is almost a 25% increase in damage with its Cryo RES Shred and additional Energy generation.  Hunter’s Path, if it ever reruns, is the best option for Melt by a noticeable margin. However, it is a much weaker weapon overall compared to the other two 5-star weapons. It does not hold up as well in AoE, it struggles outside of Melt, and it is not as universal. It is still a powerful weapon, but its strengths pale in comparison to Polar and Aqua. If you only play Melt Ganyu and you dislike managing Prototype Crescent or Hamayumi’s passives, then Hunter’s Path is better than C1. Otherwise, you are better off pulling either C1 or one of the other weapons.