The suggestion to use the env variables in the index template:

"To create the administrative user open <a href="${localAdminUrl}">${localAdminUrl}</a>, or set the environment variables <code>KC_BOOTSTRAP_ADMIN_USERNAME</code> and <code>KC_BOOTSTRAP_ADMIN_PASSWORD</code> when starting the server."

Is not correct - it is too late to use the environment variables because they are only used when the master realm is created, which would have already happened.

_Originally posted by @shawkins in https://github.com/keycloak/keycloak/discussions/35477#discussioncomment-11439894_