The boost and bury features from Rules are based on the optionalFilters parameter.
Optional filters are evaluated at the "filters" ranking criterion within the default ranking criteria.
Because Algolia uses the tie-breaking algorithm, the filters criterion affects the ranking only when precedence criteria do not break the tie.
So for example, if there is a sort-by attribute that is ranked higher than the filters ranking criterion in the Ranking and sorting configuration, boost and bury features will not take effect because the sort by attribute has precedence over any other ranking criterion:
In this case it is advised to only add a sort-by attribute to replica indices. Otherwise, lowering the custom ranking criteria below the standard default ranking criteria would enable the proper functioning of boost and bury features.