I don't think you need a post-bacc or a masters as your GPAs aren't too bad. With 5 interviews, your DAT seems to be looking ok as well, but I think they're valid for a max of 3 years for most schools, but above OSU was listed as needing them within two years so there could be others SO you could retake it and if you do better, that'd be great!
But honestly, with 5 interviews, it looks like your interviewing skills may be hindering you from getting an acceptance. So, I'd really work on interviewing. Maybe you didn't come across confident enough, maybe you were too shy, who knows, but it looks like your stats aren't your biggest red flag since you got 5 interviews when some applicants only get 2-3! Try YouTube videos, google around for interview coaches, try doing a mock interview with your pre-dental advisor, etc.
For this coming cycle, I'd apply early and hopefully you have improvements from last year (like more shadowing, volunteering, etc), and if you don't have any interviews by the time your DAT expires/midsummer, schedule a retake for August-ish maybe (unless you can do a retake before May - that would only help you if you are able to do well). But really I'd focus more on coming across as an excellent interviewee cause that's where I think you're lacking.
Good luck!
EDIT: Also for the schools you're waitlisted at currently, do send a letter of intent to your first choice, and updates to the others if you haven't already. If you get off the waitlist, then you don't have to worry about all of this other stuff anymore 🙂