The child domain controller does not have any rights, what should I do?

Question

Active Directory

As I understand it, this is how it should be, but I still have not understood the logic of this process, from the windows server textbooks that I read about child domains, it was only written that they have a full trust with root and that's it! and here it turns out that the child domain does not have Enterprise rights, and why it is impossible to configure DNS or DHCP without delegation, why is this necessary? and what is the best approach to take? to configure the same DNS and DHCP.
Give enterprise rights from root DC? that is, in fact, it’s completely right that it’s also not good, my head is already cracking from this fact.



Even better, now members of the child domain can't see the groups in the Builtin container, and I'm already slowly tearing my hair out. I feel if I continue to work with Windows, I will not only have problems with servers ....