There are several reasons why a record that exists in your index isn't being displayed in your front end. The most likely is that there is a filter excluding the item from the results being returned. It could also be that the record is being returned, but it's being pushed to the bottom of the results.
To check whether a filter is responsible, you can look at the network request in browser developer tools to check the filters that are being sent. We have a troubleshooting guide on the issue. If the filters or facetFilters sent aren't matching an attribute in the relevant record, that is likely why it is not being displayed.
If it's an issue with ranking pushing it down the record in the returned results, please see this guide on troubleshooting ranking.