In the Trial mode, the visibility of files is restricted to a maximum of 50 on each of the four tabs. To gain access to additional files and enable the ability to download beyond this limit, it is necessary to Subscribe to the Mass File Download feature.
PS: View Mass File Download, Salesforce file download app on Salesforce AppExchange: https://appexchange.salesforce.com/appxListingDetail?listingId=a0N3A00000EcsAOUAZ