Unused Enterprise applications

Try the below PS:

# Connect to Azure AD

Connect-AzureAD

# Set the number of days to check for stale applications

$staleDays = 30

# Get the list of enterprise applications

$apps = Get-AzureADServicePrincipal -All $true

# Filter out the applications that have had a sign-in within the last $staleDays days

$staleApps = $apps | Where-Object {

(Get-AzureADAuditSignInLogs -ObjectId $_.ObjectId -All $true -Top 1).createdDateTime -lt (Get-Date).AddDays(-$staleDays) 

} 

# Display the list of stale applications

$staleApps | Select-Object DisplayName, AppId