Search on different CMS and Sort by Ocurrences of the keyrword

I’m working on creating a search system for a dashboard that allows you to search multiple collections (and their fields) at once and displays the resulting items based on the number of occurrences of the keywords searched.
The idea is to present the user with the best search results package.
Can you help me with an idea of tools that can solve this?
Thanks in advance :slight_smile: