I have most of the code and the knowledge you need.
This is my plugin that does must of what you needhttps://wordpress.org/plugins/bh-staffi ... ad-for-wp/
The plugin may be all you need (doesn't integrate with WP JOB MANAGER) if not reach out.
Senior Full-Stack WordPress Developer
Partner, Paul & Gina Bearne
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Cell: +1 647 780 7594