Perhaps she has some sort of Mental health issue.
If its not something you feel comfortable addressing with her and you really dont want to deal with her then perhaps necxt time you decide to change your mobile number then dont give her your new number and cut ties. There is no rule to say we have to stay in touch with family members that bring negative energy to our lives

Have you tried to set reasonable boundaries with her? Tell her directly that you aren’t available on a daily basis, or multiple times a week. Signing you up for events sounds very frustrating. The best you can do is communicate your expectations and if they aren’t met I’d put her on a soft block for a few days.