How to override DNS resolver ordering while connected to L2TP VPN
My case was very similar. This worked:

Ordered VPN connection first in Service Order dialog -- which removes local DNS server, as you noted;

Created additional resolver for local lan:
% sudo mkdir /etc/resolver
% echo &quot;nameserver 172.16.10.1&quot; | sudo tee -a /etc/resolver/home.rossipedia.com



After that, both local and remote hosts became accessible via FQDN, such as host.first.vpn.domain and other.home.rossipedia.com.