You’re already doing a great job with brushing, that makes a big difference! Is she quite calm when you brush her? If so, you could try slipping in a gentle wipe with a lightly damp cloth or a cat-safe grooming wipe between brush strokes and see if she accepts it. Keep an eye on her body language and keep it short to begin with, rewarding her with a high-value treat afterwards so she starts to associate it with something positive. Then you can hopefully build it up a bit over time. If that doesn’t work, an air purifier can also really help manage dander in the home. There’s a great article on this topic on the cats.com website that might give you a few more ideas. – https://cats.com/cat-dander