Updating unattended EWS scripts using modern auth

OK, like I have discovered, the PartnerAccessToken does not really work for EWS. It seems the only possibility is to use the Get-MsalToken. But in first line it is interactive.
How can I get it turn to unattended?

# Provide your Office 365 Tenant Id or Tenant Domain Name
$TenantId = "contoso.onmicrosoft.com"
    
# Provide Azure AD Application (client) Id of your app.
# You should have configured the Delegated permission "EWS.AccessAsUser.All" in the app.
$AppClientId="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"  
 
$MsalParams = @{
    ClientId = $AppClientId
    TenantId = $TenantId   
    Scopes   = "https://outlook.office.com/EWS.AccessAsUser.All"   
}
 
$MsalResponse = Get-MsalToken @MsalParams
$EWSAccessToken  = $MsalResponse.AccessToken

Import-Module 'C:\Program Files\Microsoft\Exchange\Web Services\2.2\Microsoft.Exchange.WebServices.dll'
 
# Proivde the mailbox id
$MailboxName ="email address removed for privacy reasons"
 
$Service = [Microsoft.Exchange.WebServices.Data.ExchangeService]::new()
 
# Use Modern Authentication
$Service.Credentials = [Microsoft.Exchange.WebServices.Data.OAuthCredentials]$EWSAccessToken
 
# Check EWS connection
$Service.Url = "https://outlook.office365.com/EWS/Exchange.asmx"
$Service.AutodiscoverUrl($MailboxName,{$true})
# EWS connection is Success if no error returned.

What I have done now: