I am also an MS4 going through interview season, so I am by no means an expert. First things first, I agree with everything the above poster said. There are many factors that play a part in determining one’s competitiveness for IM residency, including (but not limited to): step 1 score, publications (quantity and quality), class rank, number of clerkship honors, AOA, GHHS, and step 2. Many of these things you are months away from having, so I doubt any of us here will be able to give you significant advice on which programs you're competitive for. However, I’ll offer a few suggestions as someone who has interviewed a few of your listed programs.
The biggest advice I’d give is to focus on your current and upcoming rotations instead of trying to appeal your IM grade. Considering your school has a shelf cutoff, arguing that external circumstances might have affected your performance will pose a significant uphill battle. While it’s beneficial to have support from mentors in the field, I wouldn’t risk the possibility of burning bridges with them over a grade appeal when they could possibly elaborate on it in a LOR or phone call to a PD. While a HP is not ideal, there is very little you can realistically do now to change that. Focusing on honoring your remaining rotations and crushing STEP 2 might be a better use of your time and energy.
Additionally, I don’t see much utility in comparing elective time when evaluating programs. From your post, I am assuming you want to pursue a subspecialty like cardiology, and some programs have subspecialty wards such as cardiology (GI, Onc, or Pulm, etc). It's during those rotations where you'll make connections and meet mentors which would have been formed during medical student electives. Elective time at many programs is generally used for POCUS rotations, procedural services, research, or global health rotations. That will not be the case everywhere, I would suggest focusing on factors like traditional vs. X+Y schedule, if the program has a dedicated night float or expects teams to take overnight call when making your list of programs. Also I think your current list is fine, I personally wouldn't have felt comfortable applying to only 20 programs when many people with competitive stats are struggling to get 10-12 interviews after applying to 40-50. Try to apply to enough programs that you will be able to interview and rank 15. If you have any more questions, I'd be happy to answer them to the best that I can.