Very calm female British Shorthair looking for a real home

It's quite difficult for me to write this because she's not just any cat to us. She's been with us for almost two and a half years, and honestly, she's become so accustomed to our routine that she sometimes seems like another member of the family. Her name is Misha, and she has that typical British Shorthair temperament that I've always loved: she doesn't make a fuss, she doesn't climb everywhere, and she doesn't break things out of anxiety. She prefers to sit nearby, observe, sleep peacefully, and approach us when she wants affection. In the afternoons, she usually stays in the corner of the sofa while we work or watch TV. She's not a demanding or clingy cat, but she is very present. The reason I'm looking for a home for her is that my mother started developing a pretty severe allergy, and we've tried everything for months. I don't want her to end up being passed from hand to hand or going to a noisy house because I know that would stress her out a lot. I'm looking for someone patient, who understands calm cats and doesn't expect a hyperactive pet.