Hi Ernesto Ruano,
Greetings from Syncfusion support.
Currently, We have not provided option to customize the dateModified field only for folders in FileManager component. Based on your request, we have considered this as a feature request in our end. Support for this feature will be included in any one of our upcoming releases. Generally, we will plan any feature implementation based on customer request count, feature rank and wishlist plan for some feature.
Please, track the following feedback link to know the status of this feature implementation.
We appreciate your patience.
Regards,
Sowmiya.P