How to arrange domain redirection?

Question

Domain Name System

Is it possible to somehow ensure the work of unrelated things through free dns services: hosting with a third-level domain and a domain name registrar with a second-level domain?
That is, the domain looks at the ns of the freedns server, and freedns provides redirection to the hoster's files via the third-level domain.
At the same time, a second-level domain was visible in the address bar. That is, example.ru is actually blabla.herokuapp.ru, while the ip of this blabla.herokuapp.ru is unknown - that's the whole point.

Answer 1

No, in any case, the name will eventually resolve to an IP address.

Answer 2

DNS does not deal with redirection issues. Its task is to convert a human-readable alias to an IP address and vice versa. What you describe is done by means of your hosting web server.