Admob Rewarded video and Different APK size in Alpha testing

Hello everybody, This question has 2 parts. 1.part I have in my game rewarded video ad from Admob. On admob website I haven't set any limit in showing ad per minute. In my game it shows ad is loaded but shows every second time.

2.part I have started Alpha testing on google play and uploaded apk with size 55MB. Then when i have downloaded it from Google Play game had over 80MB. Do you have any ideas how to solve these problems? Code for Rewarded video

 private void DeleteKeepGoingValue()
     {
         keepGoingValue = PlayerPrefs.GetInt("KeepGoingValue");
         if (keepGoingValue == 1)
         {
             PlayerPrefs.DeleteKey("KeepGoingValue");
         }
      
         if (AdManager.rewardedVideoAd.IsLoaded())
         {
             keepGoingButtonGameObject.SetActive(true);
         }
     }
 
 public void ShowRewardedVideoAd()
     {
         if (rewardedVideoAd.IsLoaded())
         {
             rewardedVideoAd.Show();
             LoadRewardedVideoAd();
         }
     }
 
 public void KeepGoing()
     {
         AdManager.Instance.ShowRewardedVideoAd();
         SceneManager.LoadScene(1);
     }