This doesn’t really reflect my experience with search engines.
When domains are deleted and pages disappear, search engines are usually fairly quick to delete the site from their search results. It’s not instant, and may take some time depending on crawling frequency, but it will happen.
When I search Google for site:chiucs123.epizy.com, I get zero results, meaning nothing on the site was considered index worthy to Google (they know the domain parking pages are not useful results). When I search for just chiucs123.epizy.com, the only result is the page you’re looking at right now. When I just search for chiucs123, I see many different results, but nothing that appears to be hosted by us.
What I’m trying to say is: in my experience search engines know quite well that it’s possible for domains with the same names to exist without any affiliation between them. If you have a business site, say examplecorp.com, and someone else sets up examplecorp.scamhost.biz or whatnot with something nasty, Google won’t punish examplecorp.com because someone else used the same name in their domain.
Likewise, if you have the domain chiucs123.great-site.net, it won’t matter that chiucs123.epizy.com does not show content related to you. It might be useful to have the domain anyways to avoid typo squatting, but given that it’s not possible to create new epizy.com subdomains in the first place, I don’t think you need to worry about that.
I just wrote that in another topic as well: