You can set all site settings with ENV variables (e.g., DISCOURSE_SETTING_NAME=xxx). You can change everything via the API. And sometimes as NoBugsBunny suggests, a plugin is a good way to do it.
This is beyond the scope of the free support I offer here. I don’t recommend Bitnami, but have worked with clients who use it. I’ve done a couple GKE deployments (using supported containers built with ./launcher) and am experienced with deploying and managing Discourse with Ansible. If you need help and have a budget, please contact jay@literatecomputing.com.