Setting HTTPHeaderAuthConfig (proxy authentication) upon install?

I would like to be able to configure proxy authentication in my graylog installations, directly upon install in my kubernetes setups (and hence make it part of the Helm chart I use to install it - https://github.com/KongZ/charts/tree/main/charts/graylog ) - but currently there is no (atleast not documented) way of setting this, except via UI.

I would like to be able to handle all configuration via GitOps - which is how we make sure we always have a changelog of all changes - and with ArgoCD & Kubernetes - it means if anyone edits configuration outside of GIT - I can configure ArgoCD to either "notice it" - as it notices object changes in k8s or automaticly revert any change - per my liking.