systemd-networkd looks good.

192.168.122.0 is a new network bridge for create kvm guest, looks like virt-install create it automatically today. Not sure where it define.
192.168.122.0 looks good, and can be started after reboot, but no 10.20.103.0.

?2004hubuntu@a257seubut:~$ 
route
[?2004l
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
[?2004hubuntu@a257seubut:~$ 
sudo systemctl status systemd-networkd
[?2004l
[sudo] password for ubuntu: 
[0;1;32m [0m systemd-networkd.service - Network Configuration[m
     Loaded: loaded (/lib/systemd/system/systemd-networkd.service; enabled; ven[m[7m>[27m
     Active: [0;1;32mactive (running)[0m since Fri 2022-11-18 11:11:29 UTC; 3min 3s ago[m
TriggeredBy: [0;1;32m [0m systemd-networkd.socket[m
       Docs: man:systemd-networkd.service(8)[m
   Main PID: 1404 (systemd-network)[m
     Status: "Processing requests..."[m
      Tasks: 1 (limit: 38403)[m
     Memory: 2.7M[m
        CPU: 38ms[m
     CGroup: /system.slice/systemd-networkd.service[m
               1404 /lib/systemd/systemd-networkd[m
[m
Nov 18 11:11:29 a257seubut systemd[1]: Starting Network Configuration...[m
Nov 18 11:11:29 a257seubut systemd-networkd[1404]: lo: Link UP[m
Nov 18 11:11:29 a257seubut systemd-networkd[1404]: lo: Gained carrier[m
Nov 18 11:11:29 a257seubut systemd-networkd[1404]: Enumeration completed[m
Nov 18 11:11:29 a257seubut systemd[1]: Started Network Configuration.[m
Nov 18 11:11:29 a257seubut systemd-networkd[1404]: enc1000.1300: netdev ready[m
Nov 18 11:11:29 a257seubut systemd-networkd[1404]: [0;1;38;5;185m[0;1;39m[0;1;38;5;185menc1000: Could not bring up [m[7m>[27m
Nov 18 11:11:29 a257seubut systemd-networkd[1404]: [0;1;38;5;185m[0;1;39m[0;1;38;5;185menc1000.1300: Could not brin[m[7m>[27m
Nov 18 11:13:32 a257seubut systemd-networkd[1404]: virbr0: Link UP[m
[7mlines 1-22/22 (END)[27m[K
[K[K[7mlines 1-22/22 (END)[27m[K[K[K[7mlines 1-22/22 (END)[27m[K
[K[K[7mlines 1-22/22 (END)[27m[K[K[K[7mlines 1-22/22 (END)[27m[K
[K
[?2004hubuntu@a257seubut:~$ 
sudo netplan apply
[?2004l
** (generate:2085): [1;33mWARNING[0m **: [34m11:15:00.981[0m: `gateway4` has been deprecated, use default routes instead.
See the 'Default routes' section of the documentation for more details.
** (process:2083): [1;33mWARNING[0m **: [34m11:15:01.349[0m: `gateway4` has been deprecated, use default routes instead.
See the 'Default routes' section of the documentation for more details.
[?2004hubuntu@a257seubut:~$ 
route
[?2004l
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         _gateway        0.0.0.0         UG    0      0        0 enc1000.1300
10.20.103.0     0.0.0.0         255.255.255.0   U     0      0        0 enc1000.1300
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
[?2004hubuntu@a257seubut:~$ 





ubuntu@a257seubut:/etc/netplan$ cat 00-installer-config.yaml
# This is the network config written by 'subiquity'
network:
  ethernets:
    enc1000: {}
  version: 2
  vlans:
    enc1000.1300:
      addresses:
      - 10.20.103.8/24
      gateway4: 10.20.103.254
      id: 1300
      link: enc1000
      nameservers:
        addresses:
        - 10.20.0.2
ubuntu@a257seubut:/etc/netplan$