First of all you have to define the terminology. An url without schema and domain but started from a slash is still perfectly absolute (as opposed to relative url that does not start from a slash). So, we have to keep in mind these two kinds of absolute urls.
You should only ever use relative URLs for quick and dirty pages, because the URLs will break quickly as soon as you have directories in the path.
Full absolute URLs have the advantage that if somebody is scraping your content (in a way that you want them to do) then it will still work without them doing anything. For example, RSS readers. Also, if you have links in the content, then whenever it is scraped they will all link back to your original content (good for SEO).
But relative URLs are more flexible and convenient. Ideally, use a router which will generate absolute URLs that are correct for the host on which the omegle.2yu.co PHP is being executed, but it's probably not a big deal if you use the short https://omegle.love URLs.