[keycloak-user] Default configuration of master realm

Hello, When the Keycloak server is started for the very first time, it automatically creates a master realm with default configurations. Is it possible to customize some of these default configurations during / prior to the initial deployment? For example, I want to change the master realm such that each time a keycloak server gets deployed, the master realm by default has some password policies (e.g. password expiry enabled). I know that I can override the master realm with a JSON that has the configurations that I need using -Dkeycloak.migration.file=master-realm.json and -Dkeycloak.migration.strategy=OVERWRITE_EXISTING, but I'd like to avoid the overwrite and have the custom configurations applied upon the initial creation of the master realm if possible. Does anyone have any thoughts on this? Thanks! Mike