I am working on a multi-class classification problem using TensorFlow and experiencing challenges with achieving satisfactory accuracy. I have 7 classes. Each class in a folder contains 2000 .csv files (each file have two columns). When I train the model with a binary classification approach, testing one class with another, the accuracy and val_accuracy go high, 0.85 to 0.95, but when I test with multi label 7 classes, the accuracy reaches a maximum of 0.47. Below is the code containing the data polishing and the model multi-class.