As you noted those getting hired are through via deeper human connections; through your personal network and or friends' personal networks.

Any tool to spam hiring managers whether AI or not will be marked spam which is highly impersonable, ignored and not seen.

While directly reaching out to hiring managers on linkedin might be a good thing nowadays yet with spam tools such as this Linkedin will start marking them spam and they'll never be seen.

Best thing to do to find work is through your own and or friends' personal networks as you noted.. not this IMHO.