Not sure if I understood, correctly,but to reiterate, if you can configure your own, you could host it on any hosting company. I know Name.com allows configuring NS.
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Any hosting company can serve domain ending with any extension. It all comes down to step in cpanel where you add the domain name. I have found that many hosts who have no cpanel may have this issue. So one has to get that part right. It can be harder in such case considering, how people are making web hosting to not have cpanel or zpanel. But any extension is easy to add.