Build Document collection platform (SaaS)

I need a seasoned full-stack developer who can take a B2B SaaS concept from idea to live product. It will be a secure document collection and workflow platform built specifically for lenders and financial services companies... (Budget: $30 - $250 USD, Jobs: Backend Development, Frontend Development, Full Stack Development, Graphic Design, Next.js, Node.js, PHP, PostgreSQL, React.js, Website Design)