Explanation
Graphical user interface, application, table Description automatically generated

Box 1: User2
Graphical user interface, application, table Description automatically generated

Note:
Backup Contributor - This role has all permissions to create and manage backup except deleting Recovery Services vault and giving access to others. Imagine this role as admin of backup management who can do every backup management operation.
Box 2: User3
The User Access Administrator role lets you manage user access to Azure resources.
Reference:
https://docs.microsoft.com/en-us/azure/backup/backup-rbac-rs-vault
https://docs.microsoft.com/en-us/azure/role-based-access-control/built-in-roles