There is an official Microsoft OneLake File Explorer application that may be sufficient https://learn.microsoft.com/en-us/fabric/onelake/onelake-file-explorer.

Additionally, when uploading files to OneLake there should be a specific destination that includes a workspace and a Lakehouse. There is no direct "file storage" on OneLake. Files can only reside inside workspaces, and if they are data files then the only destination is a File section in a Lakehouse.

More information can be found here https://learn.microsoft.com/en-us/fabric/onelake/onelake-access-api