var e=document.createElement("script");e.async=!0,e.src="https://cdn.sitesearch360.com/v13/sitesearch360-v13.min.js",document.getElementsByTagName("body").appendChild(e);part of the code directly in the navb.js instead of adding it as a part of the script tag inner text?
Sorry, forgot to change one thing, please try the following: https://pastebin.com/TAcZsa1K
And let me look into the rest of your questions tomorrow morning, need a fresh pair of eyes.
Mozilla/5.0 (compatible; SiteSearch360/1.0; +https://sitesearch360.com/)user agent, and the IPs listed over here, if that's helpful. But if you can wait until tomorrow, then I'll definitely look into it since a very similar request came to our mail support earlier today.