Yes. You can register an app in Entra and use certificate-based authentication to connect to Microsoft Graph. When scheduling, you can pass the app ID, tenant ID, and certificate thumbprint. It's secure too.
If you don't prefer CA certificates, you can easily create self-signed certificate using PowerShell. (preferred for internal and testing purpose only).
$Certificate=New-SelfSignedCertificate -Subject testing.com -CertStoreLocation Cert:\CurrentUser\My
After creation, you can export the certificate to the preferred path.
Export-Certificate -Cert $Certificate -FilePath "C:\$certname.cer"
You can refer to this resource for a detailed, step-by-step guide—from registering an app to creating a self-signed certificate and using it to connect to Microsoft Graph for running unattended scripts: https://blog.admindroid.com/connect-to-microsoft-graph-powershell-using-certificate/