Can relate to this.

Very few people mean what they say when you leave a job. You've also discovered that people don't want to give someone recognition for getting them out of a hole. Many lower grade employees make those further up the ladder look good. Even less get the credit.

As for LinkedIn, found it very disappointing in lots of ways. Job posts weren't relevant to my experience so never applied for any. Then had colleagues I'd never met reading my profile after I'd been made redundant from the company. In the end, just closed my account to get away from this unwanted interest. Site doesn't allow you to block a company, only individuals.

Sadly, too many companies rely on social media these days to see whether someone is a good fit. Your CV and interview performance should still be the best route.

Good luck!