Agree with above poster. Apply broadly. Last year's cycle was the most brutal in recent memory due a couple of reasons related to COVID. Virtual interviews made the investment required to complete an interview go from upwards of $1,000 to free. This, combined with the fact that the increase in the number of applicants was vastly disproportionate to the increase in spots, made it a crunch. (I theorize this latter reason was due to job market uncertainty related to COVID). The net result was elite applicants dominating interview spots at the Top Tier to Upper Mid Tier programs, when in most years these applicants would probably cancel (or not apply to as many) Upper Mid Tiers. This created a domino effect in interviews. "Charting Outcomes" interview data from prior years became essentially worthless. Even among those that did "get the interviews" I know of several people with strong profiles that had >15 interviews at solid university programs and did not match. I personally had 19 interviews, mostly at mid-tier university programs with a few top tier and a few community programs. I ended up matching at my #9. Don't get me wrong, there are still people that applied to 20 places, got 10 interviews, matched their #1 and didn't notice any difference. But the match rate dropped significantly from prior years. 80% US MD match rate is not quite the "guarantee" that someone suggested that profile was in a different thread.
Applying to many programs in different tiers is the key to optimize chances of matching. Anecdotally, the people I knew that did not match were actually stronger candidates than a good number of people I know that did. One pattern I saw is that the unmatched group had a lot of university interviews but did not have a lot (or any) safety interviews at community programs. In a year when there are more applicants applying to more places and some programs were conducting twice as many interviews as normal to protect themselves, an applicant with a seemingly "deep bench" ends up without a chair when the music stops.
If interviews are still virtual, expect something similar this year, although it might be slightly less crazy on the supply side with the economy coming back.
I have never heard someone tell me they regretted applying to too many programs; I have heard the opposite dozens of times.