This. I cannot agree more. If you think about what your data really is: Why use 64x64 (or 128x128 or whatever low resolution that necessarily has to be equal or higher than your raw data series in terms of time steps and price bins) data points and an overly complicated slow to train model instead of clean low dimensional raw data (just a few raw series and possible transformations) that underlies the image?
It's really just like taking an unnecessarily high-resolution/high-dimensional representation with lots of added waste and empty data. Think of analyzing a high-res image of a screen showing "1+1". Can you represent what should be a few bytes in machine-interpretable clean data in noisy, messy, bloated and mostly empty/sparse 3MB data? Yes, you can. But why would you?
If you really want, use at temporal RNN, CNN or other more state-of-the-art time series networks (that nowadays allow for internal multi-timefram convolution and feature interactions, see sktime, nixtla and other time series frameworks, using models like e.g. NBEATS, PatchTST, etc.) that take the clean low-dimensional time series as input. I tested it and in my opnion it did not yield any advantage over simple and blazingly fast boosted tree methods. If data is ultra noisy and signals extremely ultra-sparse, NNs are simply a bad choice. And yes, NN models are notoriously difficult to interpret, while regression or even boosted tree models can give you highly interpretable feature weights and interactions.
As
u/jawanda said: UNDERSTAND YOUR STRATEGY, then use the simplest data and model to try you hypothesis. Mean-reversion, trend, etc. Basic logic and strategy first -> test with simplest model (stat test, lin/log reg, minimal meaningful derivations/indicators on cleanly and properly standardized/scaled/log-or-nonlog price or returns data).
Tl:dr
Logic + basics >> fancy bells and wistles models
There's no way around understanding the basics of data science, statistics and your data at hand. Throwing tons of data at a fancy model hoping it will automagically find an edge and print money for you simply doesn't work. No free lunch here.
Ps: that's also how I started out, naive, thinking a fancy model might print gold for me 🤣 but I also knew "it's probably not that simple, but in the worst case I don't make any money but will learn something along the way." And I did, I learnt a lot, and that's very valuable. Plus, after 5 years working on it on the side, I think I did find some profitable strategies that I'm gonna implement and paper trade soon, taking some time off after my PhD to give it a try :)