Alright, so I've been down this rabbit hole more times than I care to admit. You're looking for those stories where the heroine isn't just a damsel waiting to get bitten. One that comes to mind immediately is 'Vampire Knight'. Yuki Cross starts off with this almost naive, protective energy, but her core is steel. She's literally raised to guard her school, and her entire identity is built around that duty. The romance with Kaname is... complicated, to say the least, because of the massive power imbalance, but she constantly fights to define her own path. It's less about her being physically the strongest and more about her emotional and moral resilience, which I find way more compelling in a gothic setting.
Another deep cut is 'Chibi Vampire' (or 'Karin'). The premise is completely flipped—Karin is the vampire, but her 'curse' is that she overproduces blood and has to give it to humans. She's aggressively normal, clumsy, and sweet, which doesn't sound 'strong' in a traditional sense. But her strength is in her stubborn compassion and her refusal to be defined by her family's predatory nature. She actively chooses a kind of weakness (her bleeding) as her form of power, which is a fascinating take. The romance is genuinely adorable and grounded in her trying to live a human life.
For something with more overt, action-driven strength, 'Dance in the Vampire Bund' is a classic. Mina Tepes is a centuries-old vampire queen in the body of a young girl, and she is a ruthless political strategist rebuilding her kingdom. She's cunning, authoritative, and the driving force of every plot. The romance with her werewolf bodyguard Akira is defined by his sworn loyalty to her, making her the undisputed center of power. It's a great pick if you want a heroine who leads nations and makes hard, bloody decisions without flinching.
Honestly, a lot of older titles from the 90s/2000s have this vibe, where the heroines had more bite, pun intended. Sometimes I feel newer stuff leans harder into the passive, 'special human' trope, which gets stale fast. You might have to dig a bit, but the ones where the heroine has her own agency, whether it's political, magical, or just sheer stubborn will, are the ones that stick with you.