If you have an "in" with somebody at the company you're applying to, then yes, that absolutely increases your chances of your resume at least being looked at by someone in the hiring chain. Barring that, though, cold calls are extremely unlikely to get you anywhere. As far as job applications go, AI-driven applicant tracking systems (ATSes) are what handle the majority of resume submissions now, and they absolutely does do not give a shit about thoughtful, artisanal resumes or job applications. More likely than not, it's a matter of what keywords an automated system seems in your resume that determines whether the company even bothers reaching out to you. And given that most companies are seeing 1-2 orders of magnitude more job applications now, it's incredibly unlikely a human is going to see your resume unless it passes the ATS filtering process.
Resume spray-and-pray is unlikely to get you good results, but that's not what the OP described. They used AI as a tool to automate parts of the resume preparation & submission process, & spent time on the parts they believed mattered.
As for pooh-poohing the 450 positions OP applied to, idk how many months they spent searching, but in terms of raw numbers that's pretty reasonable IMO. I submitted my resume to 150-175 companies over the course of 3 months before I found my job last year, and that was just before the tech job market started tanking harder -- those numbers seem low to me in today's market.