ExpanDrive is a well-regarded, cross-platform tool that mounts cloud storage and servers as a drive on Windows, macOS and Linux. It supports a broad set of backends, including S3-style object storage, and is sold on subscription. FTPie is a Windows-only file manager bought once - a different shape of tool for the same files.
The fork in the road is familiar: ExpanDrive mounts your storage so any app can use it; FTPie gives you a workspace to actively manage it.