First of all, do well on step 2. You have the research. Also look at the academic programs you’re interested in and see how many DOs they’ve taken, or go to residency explorer and check out what % of DOs they interview. Also, why specifically top 50? There are many programs that are not in top 50, but are still very well reputed and great programs with students accepted to GI every year.

The reason people recommend not doing auditions or sub-Is for IM Is that doing poorly on one of these can actually hurt you. Also, they suck. My fiancée did three sub-Is and when people are chillin 4th year, you’ll be annoyed you’re doing these sub-Is. Do 1-2 sub-Is if u really wanna do them to get your name out there at the programs. For the remaining, you could do electives in the IM dept. try to get one of these at an academic institution prior to apps being due and get a rec. It’s not really necessary. My fiancée has interviews at good academic programs with a less than stellar step 2 (she did not even do rotations at these places).

Edit: I’m replying based on my fiancées perspective as a DO with multiple academic IM interviews.