Is it possible to register NS for a third level domain?

Question

Computer networks

A second-level domain has been registered, for which the registrar has the NS-server of the registrar registered for it.
The following information is written for hosting:

@ A 1.2.3.4
* A 1.2.3.4
test A 4.3.2.1 // Another hosting

and everything seems to work.

Now I decided to create another third-level domain, and put it on a separate hosting.

Chose free byet.host.

In order to add my domain, byet.host wants me to register NS for the third level domain. As a result, I write down A - does not work, NS - does not work.
I wrote to them, explained the situation, they say it is necessary to register NS with their domains.

Question: Will this work at all? I'm talking about NS for a third-level domain.

PS. Please do not offer to change hosting. The question is purely theoretical.

Answer 1

This is called domain delegation.
In the parent domain, write:
my IN NS 1.2.3.4
my IN NS 2.3.4.5
and that's it, now on NS servers 1.2.3.4 and 2.3.4.5 create the my.comp.ru zone and fill it in as you like.
This is how second-level domain delegation works. Similar NS records are created in the ru zone for your comp domain and that's it.
And yes, for the fourth, fifth .... seventeenth level, it works exactly the same