Same problem as all AoE grenadiers, terrible damage in single target and higher levels of content. Also if you are a new player you might have missed out on her dupes and weapon, I wouldn't recommend buying her upgrades in the shop.
Recommended keys
Key 2. Silent Cheer
Key 3. Trembling Aim
Key 5. Bold Shout
BiS weapons
Heart Seeker (standard SSR)
Mezzaluna (standard SSR)
Benelli M4 Super 90 (SR)
Expansion Key
10% damage boost to higher than 0 stability target. A tiny and cost ineffective upgrade, just use your cores on something else.