Save sprite in custom folder

I'm creating an android app with Unity and I have to create a sprite dynamically, save it to a custom folder ( maybe Application.PersistantData ?) because Resources folder is not available. So here are the different steps of the process :

1. Take a photo with the camera

2. Save it to Persistant data folder

3. Load it and create a sprite with this texture

4. Save the sprite somewhere (not resources folder, this is my problem. I already did it with AssetDatabase.CreateAsset() but its not available on build).

5. Set the sprite to a scriptable Object.

Steps 1, 2, 3 and 5 work on build. My problem is step 4.

This is my code (works on editor but not on build because of AssetDatabase.CreateAsset()) :

 public class takePhoto : MonoBehaviour {
 
     // Variables
     WebCamTexture webCamTexture;
     public Character UserObject;
     private Sprite ImageUser;
     private RawImage myTexture;
     private byte[] bytesImage;
     
     Texture2D thisTexture;
     private RawImage thisImage;
     private Sprite mySprite;
     private SpriteRenderer sr;
 
     private RawImage test;
     
     private Sprite last_screenshot_save;
 
     private Image m_SpriteRenderer;
 
     private float widthSprite;
     private float heightSprite;
     private float ratio;
 
     void Start () {
         
         // Get the front camera on start
         WebCamDevice[] devices = WebCamTexture.devices;
         foreach (WebCamDevice cam in devices) {
             if (!cam.isFrontFacing) continue;
             webCamTexture = new WebCamTexture {deviceName = cam.name};
             webCamTexture.Play ();
         }
     }
 
     public void snapshot()
     {
         // Set file path
         var fileNameResources = "Assets/Resources/userPic.asset";
         var fileNamePersistantData = Application.persistentDataPath + "/userPic.png";
         
         // Take photo and save it to persistent data folder
         Texture2D photo = new Texture2D (webCamTexture.width, webCamTexture.height);
         photo.SetPixels (webCamTexture.GetPixels ());
         photo.Apply ();
 
         byte[] bytes = photo.EncodeToPNG ();
         File.WriteAllBytes (fileNamePersistantData, bytes);
         
         
         if (System.IO.File.Exists(fileNamePersistantData))
         {
             // Load photo from persistent data folder
             byte[] bytesPNG = System.IO.File.ReadAllBytes(fileNamePersistantData);
             Texture2D texture = new Texture2D(1, 1);
             texture.LoadImage(bytesPNG);
             
             // var to crop sprite to square
             var floatWidthCam = (float) webCamTexture.width;
             var floatHeightCam = (float) webCamTexture.height;
             widthSprite = (floatWidthCam - floatHeightCam) / 2.0f;
             ratio =  ((float)webCamTexture.width) / ((float)webCamTexture.height);
             
             // Create square sprite from photo
             mySprite = Sprite.Create(texture, new Rect(widthSprite, 0.0f, (texture.width) / ratio, texture.height), new Vector2(0.5f, 0.5f), 300.0f);    
             
             // Save the sprite (doesn't work on build)
             AssetDatabase.CreateAsset(mySprite, fileNameResources);
             Sprite t = (Sprite)AssetDatabase.LoadAssetAtPath(fileNameResources, typeof(Sprite));
         
             // Set the sprite to scriptable object
             UserObject.infos.states[UserObject.stateToUse].image = t;
         }
     }
 }

Can someone help ?