How to get users that have an alert set up for a list?

I’m on SPO so I’m trying my luck with my limited CSOM knowledge. Basically I`d like to get the users have set up an alert for a list.

Im able to query the alert but the "User" property is only displayed as the class name "Microsoft.SharePoint.Client.User". Heres my code:

$  ctx = New-Object Microsoft.SharePoint.Client.ClientContext $  site   $  web = $  ctx.Web $  ctx.Load($  web)  $  alerts = $  web.Alerts $  ctx.Load($  alerts) $  ctx.ExecuteQuery()  

This gives the following output if I call $ alerts:

enter image description here

Unfortunately, I don`t know how to extract the user’s email address from here.

Any ideas?

Thanks in advance for your answer.