Found a solution ( a proper one?)
- Edit file
/etc/libvirt/qemu.confafter line 504
# The user for QEMU processes run by the system instance. It can be
# specified as a user name or as a user id. The qemu driver will try to
# parse this value first as a name and then, if the name doesn't exist,
# as a user id.
#
# Since a sequence of digits is a valid user name, a leading plus sign
# can be used to ensure that a user id will not be interpreted as a user
# name.
#
# Some examples of valid values are:
#
# user = "qemu" # A user named "qemu"
# user = "+0" # Super user (uid=0)
# user = "100" # A user named "100" or a user with uid=100
#
user = "root"
# The group for QEMU processes run by the system instance. It can be
# specified in a similar way to user.
group = "libvirt-qemu"
- Restart the service:
$ sudo systemctl restart libvirtd.service
Again, I also added my account to that secondary group libvirt-qemu in a previous step.