Whom do you reachout after applying (mail / linkedin)

Hey all, I wanna ask you all people always says to cold mail or message

But whom exactly do you reach

I followed this advice and reached out to around 300+ people via mail or 100+ in LinkedIn mostly recruiters who post jobs or if i couldn't find them then I'll reachout to senior TA or I'll reachout to HR who has kept their mail-id in their posts.

But mostly i get 1% response that too after following up the mail 2-3 times.

Like If i mailed around 30 people and followed them with 3-4 times then i get only 1 responding

So, I am asking you all whom and how do you reachout. Is it Head of TA, HR executive, Recruiter or Senior Software Engineer / Manager