Thank you for asking this question on the Microsoft Q&A Platform.
You can automate that task by creating a PowerShell script, for example:
$RGs = "rg1", "rg2", "rg3"
$USER = "******@domain.com"
$RGs | ForEach-Object {
New-AzRoleAssignment -ResourceGroupName $_ -SignInName $USER -RoleDefinitionName Owner -AllowDelegation
}
With that script, you can assign the role of the Owner to multiple resources group to one user.
More info about the command New-AzRoleAssignment
Hope this helps!
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