You have reached an age when any decisions you make can be yours alone and you can base such decisions on many things.
However another persons perception of him being “manipulative “ is not something you should,imo, be relevant as he wasn’t manipulative to you, Furthermore, being manipulative isn’t a crime and although it isn’t a nice trait, you are aware of it and can take precautions. Eg if he asks you to pass in messages to siblings- “no dad, contact them directly” etc
Having a good father figure in a step dad doesn’t mean he has to be replaced by your natural father. You can’t have too many father figures. You can enjoy a friendly relationship with him without disclosing the details to your mum and siblings. If they desire to expand their relationship with him they can, keep yours to yourself.
While it is unacceptable that he broke off all contact with you all it is very sad. You don’t know if he has mental health issues or had negotiation issues with your mum, I’m not excusing him but everyone deserves a chance and we are all different.
Throughout your adult life you have to make your own choices. Allow your siblings to make theirs, and they should allow you to make yours.
Relying in other peoples account is not a good way to make conclusions.
He is wanting contact, that means as a minimum, he wants you in his life. That is credible.