Linnea is a potent support for Geo units, providing Off-Field Damage with her companion Lumi, Lunar-Crystallize DMG when Moondrifts are present, and also providing Geo Resistance shredding and teamwide healing. In addition, when Ascendant Gleam is active, Lumi can also boost the team's Elemental Mastery, and further amplifies the Geo Resistance shredding.
Linnea can feed Lumi into her Ultimate Power form to execute the Million Ton Crush, a huge Lunar-Crystallize DMG nuke.
After inputting , Lumi will continuously deal Lunar-Crystallize and Geo DMG. Inputting will lead to Lumi dealing all of her Lunar-Crystallize DMG via the Million Ton Crush, after which she will only deal continuous Geo DMG.
Both modes yield pretty similar damage, however using is generally more advisable in most teams.
Regarding Weapon Choices:
Elegy for the End: This weapon is not worth considering outside of Zibai teams.
Regarding Artifact Choices:
Main Stats
Energy Recharge: Only necessary if you need to use Linnea's Burst to the heal the team.
Substats
Energy Recharge: Only necessary if you need to use Linnea's Burst to the heal the team.
Regarding Talent Choices:
Burst: Burst talent levels are not required if you do not need to use Linnea's Burst to heal the team.