It may be time to re-evaluate how you are studying, rather than just the materials you are using to study. It's definitely okay to not have long days to study - that just means you will need to study all the same material over a longer period of time (months instead of weeks) than those who can do a lot more in a day. You can still set yourself a study schedule with goals to keep you on the right track!
While you are studying, have you been truly understanding the material? Or have you been getting the answer and moving on? There's no silver bullet to the DAT. Everyone has their favorite resource and the one they will swear by, but none of them will get you a good score by just answering questions without thinking deeply about your answers and the reasoning behind them.
I personally loved the Destroyer products. They were inexpensive compared to the alternatives, covered everything I needed to know, came in physical copies, and challenged my understanding of the important topics rather than focussing on memorization. Destroyer, Math Destroyer (+Prof Blois youtube videos), and Dynamite bio review were what I needed to do well. Plus, it seems you have it already, so might as well put it to good use.
If you want to use another resource, that's also fine. But really sit down and think about why this keeps happening. It may not be the resources, it may just be your technique. If I remember from some prior posts of yours, you do not consider your GPA on the higher end - so doing well on the DAT is pretty important, depending on where you want to go to school.
Hopefully this helps some!
