Assigning static IP to Vagrant libvirt not working

Vagrant 2.2.19, Ubuntu 20.04.3 LTS, libvirt plugin, Vagrantfile

config.vm.network “private_network”, ip: “192.168.121.101”, auto_config: false

basically the generated instance still sticks to DHCP to the default bridge. The private_network part seems to be ignored. Google’ed but it seems not much info.

Any help’s appreciated.