Start with a legal team. Seriously.

That said, I feel like this is a bit of a weird post for HN. You are asking the hardest questions of “How do I build a successful competitor to an already successful competitor?” - isn’t that the essence of founding a company?

Like i don’t want to discourage thoughtful discussions on this site and I’m not saying any rules are being broken, but it feels a bit disingenuous to be asking these questions in the sense that people that have real answers to this are probably charging REAL fees, if not already doing the whole thing themselves.