I wish OR's know their job.
The governments FY begins Oct 1st, everything depends on commission date, a commissioning date after Oct 1 means a person was selected for an FY 22 spot, that means people taking FY 22 spots would start to go to OCS basically from July 1st on, that means that the boards would pick those people starting in March of 2021 however due to COVID some that were at board end of last year were put in FY 22.
This all means that your recruiter is wrong and doesn't know what he is talking about, there is no advantage from one board to another.