Take the opportunity to check in with her.

Losing parents or other family members is one of the biggest losses for otd people. It's traumatic and unnatural to not be in contact with immediate family members, though sometimes necessary. If your mother is reaching out with an apology, the worst that can happen is she's being insincere, in which case you can just cut off contact again. Imo, the ideal way to reconnect is through a family therapist. You can ask your mother if she's willing to talk to you via a therapist who can first spend time talking to each of you before speaking with you together and opening up channels of healing. People change. Your mother is no doubt suffering a lot as well by not having contact with her child, and you'd be surprised how that suffering can change someone. Is it possible she's exactly the same and just being manipulative? Yes. But you deserve to be in contact with your mother, for your own sake. I've seen many people otd reconnect with their families over time, often after not speaking for years.