I will compile some of my server install / build fixes in here.
Just make sure you first remove default qemu that comes with debian mate / lxde before you start installing proxmox: "apt -f remove qemu-system-data". I may make a script but I don't think it is necessary for now.
auto lo iface lo inet loopback
auto eno4 iface eno4 inet static address 192.168.0.198 netmask 255.255.255.0 network 192.168.0.0 broadcast 192.168.0.255 gateway 192.168.0.1
iface eno4 inet6 static address 2001:f40:909:2482:862b:2bff:fe5f:dd02 netmask 64 gateway 2001:f40:909:2482:76da:88ff:fe7e:328d