Research opportunities are plentiful at ACOM! As part of our Foundations of Modern Healthcare (FMHC) course, every student will get a public health poster (that you present at our in-house poster day), so you're guaranteed at least 1 poster and presentation during pre-clinical. Many core sites also have research requirements (mine requires 2 case reports/presentations during third year), and our rural health rotation also provides a presentation. We also have a student organization dedicated to research opportunities, as well as a research department that regularly sends out opportunities for students. During the summer between first and second year, there is a summer research program at ACOM for which you can apply, but they will also work with you if you'd like to do research at another institution.
I was never big on research (I came into med school with none), and I'll be leaving with 4 "research experiences" on my ERAS and 6 presentations, and my specialty barely even cares about research. We had an alum a few years ago who left med school with north of 40 pubs (matched neurosurgery), so you can definitely pump your numbers far above my rookie ones.
Unfortunately, most of your rotations will not be with residents. At my site, I've had 2 rotations with residents, but most have been 1-on-1 with preceptors. Should you choose one of the bigger sites, you'll likely have more opportunities to work with residents before you get to your 4th year audition rotations. For what it's worth, I didn't feel like I had any trouble swapping from working directly with attendings to working with residents. To be honest, this is one of the biggest downsides for most DO school rotations, and I'm not aware of many that have tons of opportunities to work directly with residents.
I hope this helps! Best of luck with the rest of your cycle and your school decision!