I am new to material recognition and I hope to know if ConvNeXt easy for training material recognition. Besides, is the accuracy higher than 90 percent?

I am trying to build a CNN model in which it would recognize whether it is my face or not my face for educational purposes. However, as soon as I ran model.fit() and saw the training process, I immidiately realized that the model is suffering from a severe overfitting issue (in this case accuracy was close to 1 but val_acc remained at 0.4849). I dont know whether it is my mistake in choosing the right learning rate, epochs and batch size, or the model is too complex, or i just dont have enough data.

I want to create a deep learning model, I know how to do so with simple samples where each row of dataset represents a sample, but my samples are 2D table of numbers. The features are the same in all samples but their length (rows) varies from sample to sample, like tables below.