To be more precise, you are using Docker Engine which has no modes. Docker containers are always relying on the kernel of the host, so you can’t run Linux containers on Windows or Windows containers on Linux. Docker Desktop supports creating a Linux virtual machine on Windows, and all Linux containers rrun in that VM. That is why you can switch between Windows containers and Linux containers, because the docker client is just reconfigured to connect to another API endpoint.
Docker Desktop is not supported on Windows server, so you can only use the engine and you will not be able to switch to Linux containers mode