There is technically a surplus of residency spaces compared to NEW GRADUATES but there is also a backlog of previous graduates who got screwed by a past residency shortage plus new graduates getting displaced to make room for past graduates who didn't place. The backlog has been reduced over time but does still exist. Currently, even with the backlog if you're a new graduate you have about a 95% chance of matching, which is within the ballpark of match rates for MD schools. But if you don't match as a new grad, your chance of matching subsequent years drastically decreases.
Overall, the takeaway should be, by the time you graduate your chance of matching will be comparable to that of a new MD graduate.