C# console app to utilize MSFT_PhysicalDisk

StorageManagement.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Management;

class Program
{
    static void Main(string[] args)
    {
        Check();

        Console.ReadLine();
    }

    public static void Check()
    {
        // Specify Windows Storage Management API namespace.
        var scope = new ManagementScope(@"\\.\root\microsoft\windows\storage");
        scope.Connect();

        var searcher = new ManagementObjectSearcher("SELECT * FROM MSFT_PhysicalDisk");
        searcher.Scope = scope;

        foreach (var drive in searcher.Get())
        {
            string deviceId = "";
            if (drive["DeviceID"] != null)
                deviceId = drive["DeviceID"].ToString();

            string model = "";
            if (drive["Model"] != null)
                model = drive["Model"].ToString();

            string busType = "";
            ushort busBuff;
            if ((drive["BusType"] != null) &&
                ushort.TryParse(drive["BusType"].ToString(), out busBuff) &&
                busTypeMap.Keys.Contains(busBuff))
                busType = busTypeMap[busBuff];

            string mediaType = "";
            ushort mediaBuff;
            if ((drive["MediaType"] != null) &&
                ushort.TryParse(drive["MediaType"].ToString(), out mediaBuff) &&
                mediaTypeMap.Keys.Contains(mediaBuff))
                mediaType = mediaTypeMap[mediaBuff];

            string spindleSpeed = "";
            uint spindleBuff;
            if ((drive["SpindleSpeed"] != null) &&
                uint.TryParse(drive["SpindleSpeed"].ToString(), out spindleBuff))
            {
                if (spindleBuff == UInt32.MaxValue)
                    spindleSpeed = "unknown";
                else if (spindleBuff == 0)
                    spindleSpeed = "non-rotational media";
                else
                    spindleSpeed = String.Format("{0}RPM", spindleBuff);
            }

            Console.WriteLine(String.Format("PhysicalDrive:{0} Model:{1}", deviceId, model));
            Console.WriteLine(String.Format("BusType:{0} MediaType:{1} SpindleSpeed:{2}", busType, mediaType, spindleSpeed));
            Console.WriteLine();
        }
    }

    private static readonly Dictionary<ushort, string> busTypeMap =
        new Dictionary<ushort, string>()
        {
            {0, "Unknown"},
            {1, "SCSI"},
            {2, "ATAPI"},
            {3, "ATA"},
            {4, "IEEE 1394"},
            {5, "SSA"},
            {6, "Fibre Channel"},
            {7, "USB"},
            {8, "RAID"},
            {9, "iSCSI"},
            {10, "SAS"},
            {11, "SATA"},
            {12, "SD"},
            {13, "MMC"},
            {14, "reserved"},
            {15, "File-Backed Virtual"},
            {16, "Storage Spaces"},
            {17, "NVMe"},
            {18, "Reserved"},
        };

    private static readonly Dictionary<ushort, string> mediaTypeMap =
        new Dictionary<ushort, string>()
        {
            {0, "Unspecified"},
            {3, "HDD"},
            {4, "SSD"},
            {5, "SCM"},
        };
}

How can I do this for external disks?

It can work with external storage.
For any specific question, maybe you can ask at SO.