This, +1.
I also applied twice within 3 years. My GPA and DAT are more or less the same 3.39 oGPA, 3.41sGPA with 21AA. First time around, I received 1 interview but was rejected. But this was to be expected as I applied immediately after I took my DAT with no dental experience whatsoever. So I took a year off to strengthen my apps. I took 2 more upper div science courses (microbiology and human anatomy). I also received 3 new letter of recommendations that I knew were strong. I had 0 shadowing hours but got it up to 175hrs in a community dental clinic. Shadowed a general dentist, orthodontist, and an oral surgeon for 40, 15, and 15 hours respectively. I took dental x-ray, CPR, OSHA courses even though my community clinic did not require them. This cycle, I received 11 interview invites. 5 acceptances so far and 4 waitlists and 1 rejection (turned down 1 post dec interview inv.). I'm just trying to put things in perspective here.
With that said, I have to agree with some other posts that you need much more predental/extracurricular work. I've done research myself during undergrad and quite frankly, I would not even mention I did research if I only put in 20 hours. Even if you meant 200hr, it's not really significant imho.
For shadowing, I would shadow a general dentist for ~40hours. But I would also try to find a community dental clinic to volunteer in. Schools like NYU and (I think)UMich REQUIRES students to have at last 100+ hours of dental clinic experience.
Also definitely apply to more schools. Both you and I have mediocre GPA and DAT score. I think you should apply to more schools like Western, MOSDOH, Midwestern, and Nova even if they are relatively new. They might not have been around as long as some of the schools you listed but they are all great schools in their own rights.
Lastly, get some serious help on your personal statement. I spent about 2 months writing mine. I had mine looked over by my university career center counselor multiple times.
Good luck and don't hesitate to PM me if you need anymore insights.