I agree with the several posts above. And definitely widen your choices. This year, I have applied to 11 programs and got interviews from 5. Surprisingly, I did not get interviews from my back up choices! So it’s really important to apply to different schools as we don’t know exactly how does the selection process go. I would also recommend you to apply for more umbrella programs instead of a specific track since umbrella programs tend to interview and accept more people. Most programs allow you to transfer from track to track.
Revise and ask a lot of people to revise your statement of purpose. I edited mine for at least 20 times before I felt like it’s a good one.
As for LORs, are they strong letters? If not, that’s one thing you may want to focus on improving too. Most admission committees care about LORs the most. It makes sense because professors would rather trust and rely on things written by other professors. For me, I was in a relatively big lab and didn’t really get to talk to my PI that often. So when I had to present on lab meetings, I treated those like a thesis defense because I knew my PI’s impression was going to rely heavily on my presentation peformance.