You seem like the type of person who has great experience working through their emotional problems and I am happy to see someone actively adapting their thinking in a positive way.

I have a feeling that you are more than capable of redirecting the tone of your interactions. It might be cliche to say ‘try finding something you actually do have in common.’ I will however suggest that you might be happy to discover things about your sister. Maybe ask her questions about things that have been going on for her recently, something as simple as ‘have you been considering any hobbies recently?’ These are obviously just suggestions, but if you sincerely hear her out and show that you have a solid footing she may feel more comfortable leaning in to that support and finding that commonality of letting you open up in return.