FileCloud Drive version 21.1 and higher supports Catalina and Big Sur.
Please note that for Drive running on Apple Silicon M1, Big Sur 11.3 or higher is required and security settings have to be adjusted.
See FileCloud Drive: Configuration for Big Sur Running on Apple Silicon.
FileCloud MacDrive is a client application available for Mac OSX (Catalina and later).
It allows you to access your FileCloud server files like you would access any other files in Mac through the Mac Finder. The files can be edited from and saved directly to your FileCloud server.