Two years ago I applied to 7 programs and got rejected from them all (I have a lower GPA- and two C's in CDS coursework). I retook the two classes online at Utah State in order to boost my GPA. They were fairly expensive, about $900 each for out of state students, but I think it was worth it (this cycle I was accepted to SJSU, and waitlisted at a few programs that I was previously rejected from). Even if you apply to schools that use CSDCAS, you can add this information into your personal statement to show your dedication to this field. And when you reapply to programs, some of them specifically ask "What have you done to improve upon your application?" (Chapman University asks this via CSDCAS). If you have the time/resources to do this, it can definitely improve upon your application, especially if you also gain more work experience, volunteer hours, research experience, etc. I also highly recommend applying to the same programs you previously did, as it shows persistence and determination to attend that specific program.
Good Luck!