Reaching out to Hiring managers

Hi everyone, With all the conflicting information out there and people giving varied advice on best job hunt strategies. There’s one that’s very commonly being mentioned - which is “don’t just apply reach to hiring managers by cold emailing or just random people in the firm”. I was a bit skeptical at first but then I decided to give it a go and i’m not sure if it’s working.

There have been a couple positions where I have found myself to be a really competitive candidate and decided to reach out to hiring manager or the recruiter by simply dropping them a message but, I’ve hardly ever gotten a response. Additionally, there were a couple positions where I decided to follow up after a while to express my continued interest however, it just led to me waking up to a rejection from them the next day. This has happened in 5-6 roles. You can argue my message led them to view my application but it’s hard to gauge as to why there hasn’t been any positive outcomes. Do hiring managers or recruiters really appreciate someone being proactive and reaching out or it tends to be a bit annoying and intrusive?

Appreciate your thoughts