Currently, for UUM workspaces, we can list the groups associated with a repository https://developer.atlassian.com/cloud/bitbucket/rest/api-group-repositories/#api-repositories-workspace-repo-slug-permissions-config-groups-get, which is the opposite of the Version 1 API that allowed listing repositories associated with a group.
https://support.atlassian.com/bitbucket-cloud/docs/group-privileges-endpoint/

Please provide an equivalent Version 2 API endpoint to list repositories associated with a group. The current Org Admin API capabilities are limited to users and groups, and do not include repository or project permissions, as these are still managed under Bitbucket Cloud.