DNS for local domain (with Adguard Home)

I've just moved over from using Asus Merlin to a new router with OpenWRT.

Previously, I ran AdGuard Home inside a Proxmox VM and used DHCP to point my clients to it for DNS.

On my Asus router I ran Unbound to do external DNS lookups, and I think I was also running another DNS solution that was used for internal DNS lookups. I can't remember if it was bind or dnsmasq, but the setup worked.

My AdGuard Home DNS settings looked like this:

192.168.2.254:53535      // This was Unbound, which looked after external queries
[/mydomain.com/]192.168.2.254       //This was the other DNS server running on port 53 for internal queries

That means I could then simply type "ping laptop" and it would resolve laptop.mydomain.com to 192.168.2.135 or whatever the IP was. When a device on my LAN connected to the network, it would report it's hostname to the router and automatically pass that info off to the DNS. I didn't have to do anything manually.

I'm trying to replicate this config using OpenWRT, but I am not really sure where to start.

I found that using AdGuard home to manage this made things nice and easy, because all my clients just needed a single DNS server provided by DHCP and AdGuard would take care of the rest.

I ran Unbound to do my own DNS queries externally without forwarding to upstream. I am really not fussed abuot using TLS or DNS over HTTPS etc, I just want something basic that works.

Does anyone have any pointers or links to guides that could help me achieve this kind of setup?

Thanks in advance.