Audio File Playback on WatchOS?

I'm attempting to make a basic WatchOS app that plays a short audio clip when the user taps on a button.

I have already encoded the test audio file as 32 kbps / 16-bit stereo AAC. I found support info saying that since WatchOS 3, this meager sample rate is max allowed.

Prior to encoding the audio file down, I would get an Xcode error with my code below. But after transcoding the file to ~32kbps I no longer get the error....

BUT, even though it builds fine onto my Series 3 Watch running WatchOS 5, I cannot get any audio sound to come out. Yes I checked to ensure it's not on silent mode.

SO, my question is, what am I doing wrong if I just want the Apple Watch to play an audio file out of it's built in speaker (no bluetooth headphones). Please help!

import WatchKit
import Foundation


class InterfaceController: WKInterfaceController {

    var soundPlayer: WKAudioFilePlayer!
    
    
    override func awake(withContext context: Any?) {
        super.awake(withContext: context)
        
        let mainBundle = Bundle.main
        if let url = mainBundle.url(forResource: "testaudio", withExtension: "aac"){
            let asset = WKAudioFileAsset(url: url)
            let playerItem = WKAudioFilePlayerItem(asset: asset)
            soundPlayer = WKAudioFileQueuePlayer(playerItem: playerItem)
            if soundPlayer.status == .readyToPlay {
                soundPlayer.play()
            }
        }
        
        
        // let filePath = Bundle.main.path(forResource: "se_tap", ofType: "m4a")
        // let fileUrl = URL(fileURLWithPath: filePath)
        // let asset = WKAudioFileAsset(url: fileUrl)
        // let playerItem = WKAudioFilePlayerItem(asset: asset)
        // player = WKAudioFilePlayer(playerItem: playerItem)
        
        // Configure interface objects here.
    }
    
    override func willActivate() {
        // This method is called when watch view controller is about to be visible to user
        super.willActivate()
    }
    
    override func didDeactivate() {
        // This method is called when watch view controller is no longer visible
        super.didDeactivate()
    }

    @IBAction func buttonTapVoz() {
        soundPlayer.play()
    }
}