Add Alternate Access Mapping URL to Host Named Site Collection Zone

Requirement: Add new URL to Host named site collections alternate access mappings.
In a  SharePoint hosting Web application, once sites are provisioned from hosting control panel, We got to manually add a internet zone URL with "https" to make it available over Internet.

Host named site collection alternate access mapping
Host-named site collections are enhanced in SharePoint 2016 to allow you to add multiple URLs by using the Set-SPSite cmdlet.

• Set-SPSiteUrl - Adds new top-level URLs to a host named site collection
• Get-SPSiteUrl - Gets the list of all the top-level URLs assigned to a host named site collection.
• Remove-SPSiteUrl - This enables you to remove a top-level URL assigned to a host named site collection.

How to Add AAM URL to Host Named Site Collection's Zone?
Here is an example of adding alternate access mapping to a host named site collection.

$Site = Get-SPSite "https://intranet.crescent.com"
Set-SPSiteURL -Identity $Site -URL "https://portal.crescent.com" -Zone Internet

PowerShell script to Add new URL to internet zone for a host-named site collection:
For my requirement, I had to scan for all host named site collections, check if the site has a URL mapping for Internet zone, if not add a URL to Internet zone of the Host named site collection.

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

$OutPutFile = "D:\Scripts\Log.txt"
 
#Get All Host Named Sites of the Hosting Web Application
$SitesColl = Get-SPSite -Limit $All | Where-Object {$_.HostHeaderIsSiteName -eq $true} 

#Loop through each site
ForEach($site in $SitesColl)
 {
    #Check if site created in Internet Zone
    if( (Get-SPSiteURL -Identity $site.Url | Where Zone -eq "Internet").count -eq 0)
    {
        Set-SPSiteURL -Identity $site.URL -Zone Internet -Url ($site.Url -replace "http", "https")
        Write-host "Created Internet Zone for site:"$site.Url 

        #Append to a Log
        "Created Internet Zone for site: $($site.Url) on $(get-date)" >> $OutPutFile
    }
 }

Scheduled the script to run for every 5 minutes using Windows Task scheduler.