What you can do is create a VM (router or firewall such as pfSense®), create 2 network adapter on that VM
network adapter 1 for internal connected to Dell 10G
network adapter 2 for external/DMZ connected to DMZ 1G
Set the VMs gateway to the IP address of network adapter 2
This way between VMs you can use 10G but to the Internet will go through that VM and to Internet via 1G
