Imputing missing values
https://www.r-bloggers.com/imputing-missing-data-with-r-mice-package/
#better different methods for different variables
https://datascienceplus.com/handling-missing-data-with-mice-package-a-simple-approach/
https://www.kaggle.com/captcalculator/imputing-missing-data-with-the-mice-package-in-r
Leave the data as is and go for a model which can handle missing data (XGBoost, RF etc.)