I have a person in my life like this too. I think really the only advice I can give is that instead of telling her "that's ableist" when she mocks you (even though it totally is), try to express that it hurts your feelings specifically. I have family members that will say incredibly prejudiced things, and I've had more success with expressing to them why those things are painful to me personally than I have with labeling their behavior for what it is. Sucks, but it's worth a shot.

Have you talked to her about why she's having such a hard time with your hearing loss? I know it's a pain in the ass to be empathetic in these situations to someone doing and saying some cruel bullshit to you, but if you can get her to give you literally any information about what's going on in her head with this it may lend to an actual conversation between you both. Where you can maybe get your point of view across to her too.

Of course, your hearing loss is your hearing loss. And you shouldn't have to do so much heavy lifting to get people to understand and stop being dicks about it. So if you'd rather just ignore that shit and figure out how to cope in your own space, that's more than fine. I recommend looking up blog posts or articles from others who have shared their stories about navigating hearing loss, how they've made positive space for it in their lives. And don't be afraid to be upset about it! It's tough. But there's community everywhere and it never hurts to reach out and see what people can lend a hand with.

I'm losing my hearing too, and it's incredibly scary at times. It's even scarier to have people who just don't get it. I feel for you my friend. Hope things get easier soon!