search optimization

Hi! I need an algorithm to analyze and determine what's the best list of products for each client based on their search history. For example, a client searched for 5000 different products on my website on the last 3 months, made 1000000 searches but only converted 10 sales. I would like to keep less products available to narrow their searches into only where they are more tending to buy considering the products they searched the most, optimizing the data traffic and trying to increase the sales. I have the data history on Excel but in the future, I'll need software to pull it from an API and make it automatic. Thank you.