Daniela is the queen of making enemies murder themselves. With TSK cards, a lot of her weakpoints go away (namely Motivating speech). Keep in mind her investigator ability has no cap per turn, at all. Guard Dog, Flesh Ward, Survival Knife, Second Wind, Toe to Toe, Motivating Speech and Improvised Shield are mandatory imo in her decks.
Early upgrades should be charisma to get two guard dogs up, and spirit of humanity x2.
With those cards alone, Daniela is now absolutely murderous, tanky and will make short work of most enemies.
But it can get even more ridiculous.
"Stand Behind Me" redirects and converts all of the attacks a friend takes over to her. Keep in mind the wording of her investigator ability: attacks you provoke. This essentially means with Stand Behind Me, your friend who previously had a very annoying enemy on them can do whatever they want as you will be shredding the enemy if it hits them (a bonus if the enemy does physical damage, as your faithful guard dog can take the hit as well, dealing a whopping two total damage to an enemy completely passively, three if the enemy hits for at least two damage).
Toe to toe does a guaranteed three damage to any enemy Daniela uses it on at the cost of getting attacked (2 from the card plus 1 from her ability), and that's before guard dogs. It is hence possible to do five damage with this one card alone with her standard set up, guaranteed.
Spirit of Humanity gives a pretty reliable two horror and two damage heal every turn at the cost of adding curse tokens. This cost can actually be yet another benefit if you partner her with an investigator using curses spells, specifically Eye of Chaos and Favor of the Moon, as you will be able to more than easily keep their curse engine full.
The best part of all of this is it plays the same regardless of what difficulty you're on. Enemy abilities rarely get enhanced at higher difficulties (only thing that really changes is the bag and the penalties for drawing bs tokens). So, Daniela plays the same on easy as she does on hard.
Shes an extremely powerful investigator with a bit of a learning curve. She's not that great at punching enemies to death with weapons, she cant discover clues outside of Evidence! and she cannot ever pass an intelligence check. But she is a very strong bruiser character when built correctly, frequently making enemies take uncapped (primarily, two from guard dogs and one crom her), 3+ damage from her passives with a ridiculous amount of healing and soak and with minimal to no set up.