predicted value is more conentrated than actual with DNN
It seems like your model hasn't learnt much and may almost always be predicting the mean of the target distribution. Please check if the mean of the actual target variable resides in the 1260-90 range.
This may happen if your features are not correlated to the target.
Also, by looking at your graph, the MAE is certainly larger than 5%.
You want to collect more informative features for tour model.