F2P players will likely have no 5-star weapons to give to Yelan in Genshin Impact, so they often have to settle with 4-star variants. Unfortunately for them, there aren't any 4-star bows that buff Yelan's HP, so they will have to focus on weapons that boost other stats integral to her playstyle.
Honorary mentions should go to the Recurve Bow, as it's the only bow aside from the Aqua Simulacra that can boost a bow user's HP. However, since it's a 3-star weapon, it's technically not eligible for this list. It is better than most 4-star options for Yelan, hence the honorary mention here.
If all the player wants is to boost Elemental Burst DMG, then The Stringless is a good option for Yelan. It doesn't require as much setup to use as Mounn's Moon, although its Elemental Burst DMG potential isn't as high as Mounn's Moon, either. At the very least, The Stringless is capable of boosting Elemental Skill DMG as well.
Another advantage for The Stringless is that it's easier to R5 than Mounn's Moon by virtue of being available on banners where it's not featured. Still, The Stringless is one of Yelan's most niche options regarding 4-star weapons in Genshin Impact, and players should have access to some other great options (like Favonius Warbow).
If the player has a battery to generate energy for Yelan (like the Raiden Shogun), then Mounn's Moon is an excellent weapon to consider. Her Elemental Burst is capable of dealing a great amount of damage on its own, so having the potential to boost its damage anywhere from a maximum of 40 to 80% (depending on Refinement Level) is amazing.
It is not recommended to use this weapon outside of teams that can help her generate Energy quickly, as this bow generally suits teams with high Energy Costs.
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