How to select between models when AUC scores are similar?
Based on the AUC score they are the same. It does not really matter if the model is overfitting or not. What matters is how well it performs on new data (test score).

Overfitting is just an indication that there might be room for improvement by making your model more general. But until the test score has increased the model has not improved even if it is overfitting less.