I want to abandon my 16 year old daughter
Why would you want to abandon your daughter? How would she feel about your decision?
I think she will do better without me (she has autism and needs support).
You should reconsider abandoning your daughter, especially since she needs help dealing with her autism. You mentioned that she needs support, and she will get less support without you in her life. Look for some community programs that can help you finds ways to support her while staying in her life.
I leaning towards giving up.
You are a terrible parent giving up on your autistic daughter. You should be her strongest pillar of support.