Permissions needed for Service Principal

Is there a guide on how to create an Azure AD registered app (aka Service Principal) that has permissions to use these powershell commands?

I created an 'App Registration' in our Azure Active Directory.

I had our global admin grant it the 'Read and write all content in tenant' and 'View all content in tenant' permissions

I login successfully:

$tenantId = '<redacted>'
$applicationId = '<redacted>'
$key = '<redacted>'

$secureKey = ConvertTo-Securestring -String $key -AsPlainText -Force
$credential = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $applicationId,$secureKey

Connect-PowerBIServiceAccount -ServicePrincipal -Credential $credential -Tenant $tenantId

Environment : Public
TenantId    : 
ClientId    : <redacted>
Password    : ********

But I get an unauthorized error from any of the commands:

PS> Get-PowerBIReport
Get-PowerBIReport : Operation returned an invalid status code 'Unauthorized'