I am trying to determine if a simple train-test-split is valid for a time series if I use a Recurrent Neural Network (LSTM). Lets say I have samples (x) which consist of 2 days values (time steps) and the y variable represents the day after (ie. I have day 1 and 2 as one of the x samples and want to predict day 3 (y)). In this situation, do we need to make a train test split based on dates, or I can just do the basic split since the RNN will have as input always the 2 days prior the one I am trying to predict? I trained using the simple split and got better results than using date related split, so I am trying to check if I am not "lying" myself doing the wrong split. I know that common time series techniques need to split acording to dates but I am unsure if a RNN does to.
Thanks in advance