Relaunch\Reload RewardedAd

Hello,

When my users launch the rewardedAd, I would like they can do it again in maybe 10 minutes, but if I execute the button to show the ads a second time, I'm still locked on the ClosedEvent.

So I tried a custom code to unsubscribe all event and create new RewardedAd request in ClosedEvent, But that's not working ...

     public void HandleRewardedAdClosed(object sender, EventArgs args)
         {
 
             //unsubscribe
             this.rewardedAd.OnAdLoaded -= HandleRewardedAdLoaded;
             this.rewardedAd.OnAdFailedToLoad -= HandleRewardedAdFailedToLoad;
             this.rewardedAd.OnAdOpening -= HandleRewardedAdOpening;
             this.rewardedAd.OnAdFailedToShow -= HandleRewardedAdFailedToShow;
             this.rewardedAd.OnUserEarnedReward -= HandleUserEarnedReward;
             this.rewardedAd.OnAdClosed -= HandleRewardedAdClosed;
 
             this.rewardedAd = new RewardedAd(adUnitId);
     
             //Newsubscribe
             this.rewardedAd.OnAdLoaded += HandleRewardedAdLoaded;
             this.rewardedAd.OnAdFailedToLoad += HandleRewardedAdFailedToLoad;
             this.rewardedAd.OnAdOpening += HandleRewardedAdOpening;
             this.rewardedAd.OnAdFailedToShow += HandleRewardedAdFailedToShow;
             this.rewardedAd.OnUserEarnedReward += HandleUserEarnedReward;
             this.rewardedAd.OnAdClosed += HandleRewardedAdClosed;
     
             AdRequest request = new AdRequest.Builder().Build();
             this.rewardedAd.LoadAd(request);
         }

Do you have an idea how to launch the RewardedAd a second time ? Thanks