Ineffa transforms all instances of the Electro-Charged reaction into Lunar-Charged while she's in the team, which has its own scalings and can even crit. Both her Skill and Burst deploy her robot companion, Birgitta, to the field, who can deal damage and apply Electro while off-field. Additionally, Ineffa's Skill can also provide a shield. Her Burst also provides an Elemental Mastery buff based on a portion of Ineffa's ATK (her A4 talent).
Birgitta stays on-field longer than both of Ineffa's Skill and Burst individual cooldowns, meaning that Birgitta has 100% field uptime.
Regarding Weapon Choices:
Ascendant Gleam assumed here; Ineffa uses Burst every other rotation unless she uses an ER weapon
Staff of the Scarlet Sands: Can sometimes utilize Elemental Mastery Main Stats.
Deathmatch: Ranking assumes single target scenarios. At [R5], this weapon performs equal to .
Ballad of the Fjords: At [R5] this weapon will perform closer to .
Prospector's Shovel: Performs slightly worse than outside of Ascendant Gleam teams.
Regarding Artifact Choices:
Sets
Tenacity of the Millelith (4): This is a more supportive artifact set that sacrifices Ineffa's personal damage in favor of an ATK% buff and an increase to her shield strength.
Main Stats
ATK%: Preferred over DMG% as Ineffa's A1 does not scale well with DMG%.
Substats
Energy Recharge: When Ineffa has higher Energy Recharge requirements (typically 140%+), building ER to use her Burst every rotation results in a personal damage loss in exchange for more uptime on her teamwide buff. Teams with Ineffa as a significant source of damage will want to use her Burst every other rotation and ignore ER.