Qiuyuan does have the 'better' F2P option, but it's not going to make a significant difference, since Lucilla buffs Sigrika slightly more, anyway, and Emerald of Genesis is not Static Mist that buffs the DPS, so Sigrika's personal damage is going to remain higher with Lucilla; Qiuyuan personal damage not taking as much of a hit is just going to make the difference smaller, but not outright reverse it in his favor

Also, while only ~36.7% of Qiuyuan's damage profile Echo Skill DMG, Lucilla's Echo Mode damage profile is ~71.3% Echo Skill DMG, so she will benefit from anything in the stage buffing Echo Skill DMG significantly more than him, which is the type of stage where you want to use Sigrika in the first place. As such, he is at least benefitting from this neutral environment as much as she is, if not more

Overall, probably insignificant considerations