iOS can't get audio focus when app in background

I am wondering if it's possible to obtain audio focus when the app is in the background without using the duckOthers option. I tested the Amazon Echo buds with the Alexa app and found that it can obtain audio focus. I am curious about how this is accomplished.

I have a BLE device that can connect with my app. After connecting the device and my app, I put my app in the background and play a song from the Spotify app. Then, when I press a button on my BLE device, it sends a BLE command to my app to play music. However, my app cannot obtain audio focus, so the music cannot be played. The only way to make it work is to configure duckOthers.

Compare with Echo buds, if we do the same steps, it can get audio focus. Is it because it has the MFI?

do {
            let options: AVAudioSession.CategoryOptions = [.allowBluetoothA2DP, .defaultToSpeaker, .duckOthers]
                
            try audioSession.setCategory(.playAndRecord, mode: .spokenAudio, options: options)

            DDLogDebug("\(LOG_TAG) \(#function) setting category: \(audioSession.category.rawValue), " +
                       "options: \(audioSession.categoryOptions.rawValue)")
        } catch {
            DDLogWarn("\(LOG_TAG) \(#function) Failed to configure audio session: \(error.localizedDescription)")
            
        }
    }