Understanding CoreBluetooth scanning and connection flow

Question

I'm experimenting with CoreBluetooth and I stumbled across something that I don't understand. While scanning for nearby bluetooth device, when I log the results I don't quit understand the output, for example - Some of the devices that were found:

discovered peripheral =  <CBPeripheral: 0x281b7c140, identifier = FC3098A3-426F-F1CF-C053-1D62E3EDE473, name = (null), state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b78000, identifier = 3313CAC4-3D8F-C225-4ABB-73390CCA1DC3, name = SL-1000S_BLE(ATT), state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b640a0, identifier = D509D6C8-F5C4-E2E5-9387-B6294BCA5396, name = (null), state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b78140, identifier = A2DC3485-F341-4AAB-6B09-8816FFACA15A, name = (null), state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b7c280, identifier = 89069574-F6F9-0637-1723-FEB36C3EE2B8, name = (null), state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b78280, identifier = 792BCEC8-471F-2327-6AD1-33EC57F2A758, name = (null), state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b783c0, identifier = B7A4C076-D761-5646-0E66-DA832A9061BB, name = Amazfit Band 5, state = disconnected>
discovered peripheral =  <CBPeripheral: 0x281b7c3c0, identifier = 759BD68B-0E48-F0D6-1C08-43F4D2DA528A, name = (null), state = disconnected> 

Why some of the devices, have a name, and some have null as a name?

Another thing, I have an Android phone with Bluetooth on but I don't see it in the result logs. The only way I can see the Android device is if I manually go to iPhone's Bluetooth settings find the Android device in the scan results* and connect to it manually. After connecting manually I see that following log:

discovered peripheral =  <CBPeripheral: 0x281b790e0, identifier = 7E34D617-731F-616E-8C89-5729870CDD5E, name = Edward's Galaxy S9+, state = disconnected>

Now, after connecting manually why is the state of the connection says disconnected even though if I go to settings I see that it says that it is connected?

One more thing, why while scanning for the devices in the Bluetooth settings I do see the device, but the results of the scans of my app it doesn't appear?

Here's the code snippet:

override func viewDidLoad() {
        super.viewDidLoad()
        
        centralManager = CBCentralManager(delegate: self, queue: nil)
    }

func centralManagerDidUpdateState(_ central: CBCentralManager) {
    
    switch central.state {
        case .poweredOn:
            print("poweredOn")
            self.centralManager?.scanForPeripherals(withServices: nil, options: [CBCentralManagerScanOptionAllowDuplicatesKey:false])
            break
        @unknown default:
            print("default")
            break
    }
}

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {

    if(!peripheralsArray.contains(where: { $0.identifier == peripheral.identifier})) {
        print("discovered peripheral = ", peripheral)
        peripheralsArray.append(peripheral)
    }
 }