2. Every application is reviewed by a real human against the job qualifications, and the highest qualified applicants are shared with the hiring team for consideration.
More information on USAJOBS' process is available here: https://www.usajobs.gov/Help/faq/application/process/
That said, having been through various versions of this process since 2004, it is extremely valuable to get visibility on candidates who may feel "stuck outside the system". Not only is it increasingly the case that the best candidates are precisely the ones who feel stuck outside, I can't advocate to fix the system without putting those cases in front of the HR people who are responsible for the system.
If a federal manager is giving you an email inbox for their applications, they are begging for your help. If you want a job, sending email to that inbox is helping them, and they will appreciate it.