Creating dataset - imbalanced or balanced?
The easiest option to close your approach is too just run the model twice in both variations. But in my experience this specific data is bound to be imbalanced.
Your idea to fix the class imbalance is technically known as under-sampling. This is one technique which is used. You can try out a few other techniques which are mentioned here: https://www.kdnuggets.com/2017/06/7-techniques-handle-imbalanced-data.html