I was in your spot almost 20 years ago. I didn’t invite my parents to my wedding. I knew they would use it to hurt me. My day was great, friends became family, and I felt loved and supported on my wedding day.
Ultimately it is up to you, but don’t be naïve that your family will choose your happiness over the cult, they won’t.
Comgratulations on your engagement - enjoy this time with your fiancé.