With the Bookmarks feature, Alfred indexes and searches for your bookmarks, removing the dependence on the macOS metadata.
Grant Alfred Access to Your Bookmarks
To use the Bookmarks feature, don't forget to grant Alfred Full Disk Access permissions via Alfred's General Preferences > Request Permissions...
You can include results from both Safari and Google Chrome to your results, and can choose to either include bookmarks in your default results (more convenient) or prefix them with a keyword (lower results noise), which is "bm" by default.
Safari will include your Reading List in the results.
It's also up to you whether the bookmarks are opened in the bookmark's source browser, or always in your default browser.
If you previously included bookmarks in your default results, you'll need to re-enable them under Features > Bookmarks.
Note that this preference isn't synced between your Macs to allow different settings per Mac, so you'll need to enable it on each Mac respectively.