The Eventlog Trigger
The Eventlog trigger allows you to start an application or a PowerShell script for a specific Eventlog entry. This blog describes the automated creation of such Scheduled Tasks with PowerShell and the possibilities to use such a task as a service replacement. Such a script can also always be started with system rights or as a "Network Service" (in this case the permissions of the computer are used for the network access). In the end, a small write access to an event log is sufficient. This can be created by the user.
New-EventLog -LogName 'MyEventlog' -Source 'powershell.exe'
As a rule, a user may write to such a log. But of course write access can only be allowed for certain users and groups. For this I found the following blog. But there are also other possibilities.