New tool for eBay sellers: How would you build this verification system?

Hi everyone, I'm currently developing a new tool for eBay sellers that analyzes shops based on data such as delivery times, reviews and product range and calculates a score. ​The vision: Bring more color and gamification into everyday retail life. Sellers can compete playfully using a public leaderboard. The tool shows you exactly where you can improve in order to boost your score, optimize your performance and thus be at the top of the eBay search results