This KB includes an example how to install HF1 when using Offline Mode and Cluster Administrator Role
DX Platform 21.3.1
See attached: Example How to install 21.3.1 HF1 - Offline Mode + ClusterAdministratorRole.docx
The official procedure is documented in Techdocs: https://techdocs.broadcom.com/us/en/ca-enterprise-software/it-operations-management/dx-platform-on-premise/21-3/Upgrade-DX-Platform/Upgrade-2131-to-2131HF1.html