Hi @Matheus Sonego ,
Please note that Get-MgAuditLogSignIn MS Graph PowerShell SDK command uses List signIns Graph API in the background. ** Currently this List signIns API retrieves the Azure AD user sign-ins for your tenant. Sign-ins that are interactive in nature (where a username/password is passed as part of auth token) and successful federated sign-ins are currently included in the sign-in logs.** Hence this List signIns API or MS Graph PowerShell SDK command is not returning non-interactive user signins data.
However upon my further research, there is "Sign-in logs" option available under "Monitoring" section of Azure Active Directory as you can see below and I could see both interactive and non-interactive user signin logs information. Also , we do have the options such as filters and download report in Azure AD portal. You can also review the same and see if it's useful to you.
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