You observe that the Identity Broker fails on the VC user permission precheck in VCF Operations.
Required privileges [Authorization.ModifyPermissions, Cns.Searchable, Global.ManageCustomFields, ServiceAccount.ManageAccount, ServiceAccount.Administer, Global.SetCustomField, Authorization.ModifyRoles, ServiceAccount.ManageAccount,ServiceAccount.ManagePassword]

The precheck validation fails because the service account permissions are granted at the group level instead of being assigned directly in vCenter. The validation mechanism does not properly detect privileges inherited through group membership.
Method 1: Assign Permissions Directly
Add the user account permissions directly in vCenter with the required privileges. You can view the required privileges to deploy the Identity Broker in the Installing VCF Identity Broker documentation.
Method 2: Ignore the Precheck
If you are certain the service account has the proper permissions via its group membership, you can safely ignore the precheck failure and proceed.