You can use the SaaS Loopback Connector to manage User-Levels as Entitlements.
IdentityNow Management Connector - CoLab / SaaS Connectors - SailPoint Developer Community
Below is also a post explaining how to configure the web service for management.
Assign ISC Capabilities with Requestable Entitlements/Roles - Identity Security Cloud (ISC) / ISC Community Knowledge Base - SailPoint Developer Community