Having the same issue, but I'm on GCP and using Approach B, self contained.
I've added the following inside of <Directory /"right carrot" within the /opt/bitnami/apps/phpmyadmin/conf/httpd-app.conf:
<Directory /"right carrot"
</Directory "right carrot"
I've also created a password for Administrator, but every time I go to sign in to phpMyAdmin it doesn't ask for double login, just the one "root" / generic password login.
Also, can't find a "/users" directory in "/opt/bitnami/apache2/"