So basically I do not want to use endpoints on Syncfusion's file manager component. Instead I want to feed it with an object that stores the data I want to show.
Docs explain how to integrate the file manager with many options like ftp, sql, cloud services... just by giving value to ajaxSettings (file system provider docs). Also, most of the configurations differ in the url, which seems to point to an internal component that I couldn't reach (giving me a sense of distrust if they ask to put AWS secret keys to configure s3 access...)