Explanation
The most maintenance-free way to ensure a Conjur host's access reflects any changes made to accounts in a safe in the CyberArk vault is to grant the consumers group/role created by the Synchronizer for the Safe to the host. This means that the host will inherit the read and execute permissions on all the secrets in the Safe from the consumers group/role, and will automatically get access to any new or updated secrets in the Safe without requiring any manual intervention or policy changes. The consumers group/role is created by the Vault Conjur Synchronizer, which is a service that synchronizes secrets between the CyberArk vault and Conjur. The Synchronizer creates a policy branch for each Safe in Conjur, and assigns the consumers group/role to have read and execute permissions on all the secrets in the Safe. The Synchronizer also creates a delegation policy for each Safe, which allows the Safe admins to grant permissions to other users, hosts, groups, or layers12.
The other options are not the most maintenance-free ways to ensure a Conjur host's access reflects any changes made to accounts in a safe in the CyberArk vault. Writing an automation script to update and load the host's policy using PATCH/update may work, but it requires additional effort and maintenance to ensure the script is always running and up to date with the changes in the Safe. Using yami anchor [&] and wildcard (*) syntax to maintain its list of permission grants may simplify the policy writing, but it still requires manual editing and loading of the policy whenever a new secret is added or removed from the Safe. Using PVWA to add the Conjur host ID as a member of the Safe may not be possible or advisable, as the PVWA is designed for managing human users and not Conjur hosts, and it may not have the necessary integration or authorization to do so3. References: = Vault Conjur Synchronizer 1, Synchronizer Policy Structure Grant permissions on secrets 2, Grant role permissions on all secrets in a Safe Privileged Access Manager - Self-Hosted 3, Privileged Web Access (PVWA)