at the moment it is not possible to secure rooms with an additional password. Instead we recommend to use long randomly generated room names.
This is possible, but not exposed as a configuration setting in the app settings. Since Meet is an app based on docker-compose one can however easily extend/override individual parts of the app. The configuration setting to modify is kwmserver/scripts/kwmserverd.cfg at master · Kopano-dev/kwmserver · GitHub and for this service settings are read from the environment of the container. This can be achieved by placing a files called docker-compose.override.yml needs to be created in /var/lib/univention-appcenter/apps/kopano-meet/compose with the following content: