WordPress Meta Pixel Fix

My WordPress site’s Meta (Facebook) Pixel has stopped capturing data—Events Manager shows zero activity. The issue started several months ago, I am not sure exactly when and why.
I upgraded Meta Pixel plugin to the latest version, but it does not support the old PHP version I am using.
When I try to enable the updated Meta Pixel plugin my site admin is breaking, so I disabled the plugin.

I am using an old theme. When I try to upgrade my site to a supported PHP version, plugins are breaking, and site is not working as expected.

I do not want to replace the theme I am currently using because I am very happy with the look and fill of the site.

I tried adding the meta pixel in the headers of all my web site pages using a header plugin. Although headers look as it should with the required script and pixel number, I do not see any events in Events Manager.

I’m looking for someone who can fix the issue.
If it is possible, I prefer to update the theme to support current PHP versions.

Deliverable (acceptance criteria):
• Pixel loads on every page and records all standard events.
• Meta Pixel Helper shows green checks.
• Events Manager displays live traffic within 24 hours of fix.

I can provide full backup of my site (www.inbalhealing.com) so you can test this in your own environment.

Thanks, and good luck to all bidders.