Only real expertise in the field of payments can manage a project properly. Because the difference between payments and other matters is that they are never in a closed environment but are open systems by definition.
This may seem paradoxical with the above, but as much as payment systems are never closed in on themselves, the standards, methods and techniques they use are very specific and, it must be said, often obscure for people outside the domain. Surrounding yourself with real specialists should be the priority when starting a complete transformation project or program.