A Recruiter’s Perspective: What’s Going On?

I’m seeking insights from recruiters regarding the job application process in the UK.

Earlier this month, I applied for a position on LinkedIn that aligns with my qualifications. After reaching out to the hiring manager, we had a productive conversation, and he assured me that I would be a strong candidate for the interview pool.

However, it’s been about 3-4 weeks since my application, and I noticed the job has been reposted. Does this mean I still have a chance? Could it imply I was a contender but ultimately not selected? Do recruiters typically aim to have a certain number of candidates in the interview pool before they begin? Additionally, when is an appropriate time to send a follow-up without being overly persistent?