It's not possible to update the rules of the SG at the moment.Some contributors are working on a feature that would allow ICMP echo requests on the VIP of a load balancer:910963: Config option to allow ICMP echo requests on VIP | https://review.opendev.org/c/openstack/octavia/+/910963
Customizing the SG of the VIP port is also a feature that has been requested on numerous occasions, we will discuss it during the next PTG in April.