Develop Ios Apps On Windows. You don't need to buy a mac!. This is called virtualization, and it allows you to run windows on linux, os x on windows, and even windows on os x.
So yes, while you can generate the xcode project on your windows machine, you won't be able to do anything with it there. My advice is to keep using your current system (windows or linux) for as long as you are learning and even while you are developing your first flutter apps. This means the main developer tool for macos, xcode, can be used only with this operating system.
However, apple's native frameworks used for developing ios apps cannot compile on other platforms like linux or windows.
You don’t need a mac, in order to develop ios apps on flutter. A virtual machine will create an environment where any operating system can run in like it’s running in the same hardware itself. A refurbished mac mini (~$500) will do the job. Native ios development tools like xcode only work on a mac.