Guys, go to builtwith.com, enter your domain and search, and then navigate to the “Relationship” tab.
You’ll see how your sites are connected to each other through GTM, GA4, and other tag tools.
You’ll see sites using the same Adsense code (or any other advertiser code), as well as numerous identifiers for revealing networks (and yet, “SEO specialists” claim that Google simply uses GSC for detecting and banning sites).
You’ll also get some information about IP addresses if the hosting is shared.
Split the sites into different accounts to be on the safe side.
If you see domains that don’t belong to you, it may mean that pages from your site have been copied and posted on another site without removing your tags.
Yes, in some eastern parts of the planet, there is a trend of literal theft through blind copying of HTML pages.
They pay no attention to scripts and tags.
They even copy and post pages with noindex tags.
Additionally, on BuiltWith, go to the “Redirects” tab and see which domains 301 redirect to others.