Assalamu alaikum - Questions About Moving Between Sects and Family Concerns

Assalamu alaikum everyone, I’m a young-ish sister still living at home. My family are very devout Ahmadis, and my siblings and I don’t share the same views. Leaving the community feels almost impossible because we’re so tied to it - social ostracism, losing family and community, generational pressure, emotional blackmailing. It hurts me to think about upsetting my mother and it brings me to tears often. I’ve been doubting since childhood. My father actually stopped believing years ago but, like us, hasn’t really left; he’s distanced himself and doesn’t attend their mosques anymore but quietly keeps his distance. I have a few questions. If I want to follow mainstream Sunni Islam, is there a formal conversion process I need to do? Do I need to see a local imam or sheikh? Should I explain my family situation to them? Also, any advice on coping with the emotional blackmail and the guilt of hurting my mother would be so helpful. I don’t want to cause her pain, but I can’t keep living a lie. As I get older I worry about marriage - would another Muslim family accept me if I leave a sect? Could my father still act as my wali if he’s effectively distanced himself? JazakAllah khair for any practical advice, personal experiences, or duas. I’m really lost and would appreciate guidance.