YukikoLimited

Used as a top Fire DPS in Solo Raids against Wind Code enemies (= Fire advantage), while also healing all allies to save a healer slot.
Her solo damage is slightly below Rapi: Red Hood, and with Makoto they exchange Increased ATK through 1more for even more damage.
1more-related effects only trigger when Wind Code enemies are present, and she relies heavily on normal attacks, so her value is much lower in other-element boss fights and the Arena.

From battle start she has a permanent Attack Damage increase, and at battle start and when Full Burst ends, she gains Increased ATK for 15 seconds each time. Persona - Konohana Sakuya heals all allies every 3 seconds based on final Max HP, and using her Burst applies Scarlet Flower2 until Full Burst ends, adding another heal, raising her distributed damage, and reducing damage taken from Water Code enemies. On entering Burst stage 3, she gains Elemental Advantage Attack Damage increase.

If Wind Code enemies are present, 1more triggers on Burst, dealing distributed damage to all enemies and granting Pursuit Increased ATK for 25 seconds to a Persona-state ally whose base Burst stage is Burst 3 (Makoto). Even with distributed damage, most of her damage comes from Machine Gun normal attacks, so missing the core cuts her damage greatly.

Auto is fine by default.
In a squad with Makoto, Makoto uses Burst stage 3 first and Yukiko follows.

Use whichever of Bastion Cube or Resilience Cube is higher level to keep Machine Gun fire going.

Normal attacks make up most of her damage, so secure Max Ammo and fill remaining slots with Crit Rate and Crit Damage.

Healing and Increased ATK are on S1, while permanent Attack Damage increase, Elemental Advantage buff, and Pursuit are on S2, so raise both skills first. Her Burst is a single round of distributed damage, so do it last.

Used with Makoto in Solo Raid boss fights against Wind Code enemies (= Fire advantage). Also used in Special Interception when you want one unit to cover both Fire DPS and ally healing.

A Fire DPS who also heals all allies every 3 seconds, saving a healer slot.
She can be used as a solo DPS even without Makoto.
Her constant healing meets Crown's skill trigger condition.

1more-related effects only trigger when Wind Code enemies are present.
Her self Increased ATK is large, so adding several ATK buffers lowers efficiency.
Her Damage Taken reduction against Water Code enemies rarely matters in practice.

A limited Persona collab Nikke.