nixCraft published a tutorial about adding a network bridge (br0) with nmcli command in Ubuntu 20.04 LTS.

Ubuntu 20.04 add network bridge (br0) with nmcli command

Explains how to configure Ubuntu 20.04 LTS server & add network bridge (br0) with the nmcli command. Useful to create a network bridge for KVM.

Ubuntu 20.04 add network bridge (br0) with nmcli command - nixCraft