You should review our guide here on custom ranking for insight into how you may want to compute various values into one that can be used for ranking purposes.
For example, one workaround is to add a boolean attribute to your records, set the ones you want to boost to a true value and use the optionalFilters. The way that the boolean attribute is calculated could be the result of various metrics that meaningful for your use case (e.g. popularity, sales, votes etc.).