Multi-Platform Social Content Plan

I need a clear, actionable plan that tells me exactly what to post, where, and when across Instagram, Facebook, LinkedIn, X (Twitter), and Nextdoor. My priority is the planning and scheduling side of social media rather than paid ads or follower-hacking tactics... (Budget: $8 - $15 USD, Jobs: AI Graphic Design, Book Marketing, Content Creation, Content Strategy, Content Writing, Digital Marketing, Facebook Marketing, Instagram Marketing, Social Media Management, Social Media Marketing)