Is it possible to make an alias for a domain?

Question

Domain Name System

Greetings!
I have at my disposal the domain.ru domain and the "dynamic-dns" my.ddns.ru domain.
So far, it has been possible to make alias only for the subdomain. That is, sub.domain.ru = my.ddns.ru.
But you cannot specify an alias for the domain itself. Why is that? Can something be done about it?
From a security point of view, absolutely any alias can be specified for a subdomain, why is it not yet possible for the domain itself?
The domain itself is currently located on Yandex, and mail is also used there. Maybe it has something to do with it? I don't want to pay for hosting.

Answer 1

https://support.rusonyx.ru/index.php?/Knowledgebas...
but you can send an alias to the same IP, if of course your server and IP is controlled