Is it possible to set up two different AD domains on the same /24 network?

Question

Domain Name System

There is a network 192.168.137.0 /24 . Raised on OpenWRT (NAT, DHCP, DNS).
There is a configured working AD domain on Server 2019. (The role is only a domain controller, DNS and DHCP performs OpenWRT)
I connected another Server 2016 with a different root domain to the same network (also only the role of a domain controller).
In OpenWRT in /etc/dnsmasq.conf I wrote the entries srv-host=_ldap.-tcp.dc._msdcs...... etc. for both servers.
But users from the second domain cannot log in to the PC (also from the second domain). No server was found capable of handling the login (like it says).
I feel that the problem is either in the dnsmasq configuration, or in one network there can be only one domain controller (like one DHCP).
Help :)
I know what looks like perversions, I know that according to the instructions, DNS and DHCP should be on the domain controller, and that you can migrate users by making two domains from different subnets ..
But I just need the old domain to be available for a while while I'm from scratch I make a new one. Please don't ask me why I'm doing this and don't throw slippers. Let's pretend that I'm really stupid and stubborn, and I just want to understand why it doesn't work.
I can throw configs / outputs nsoookup, ip config, etc. (if needed)

Answer 1

Establish trust relationships between domains.

Answer 2

You can leave DHCP on the router, and it is better to keep DNS on domain controllers, so there are fewer headaches and bugs with updating service dns records. If you want both controllers to exist on the same network, then either specify the necessary dns servers on the computers statically, or specify different options for computers from different domains in the DHCP reservation.