Blank screen and log off - Windows Server

It seems like you're experiencing an issue with your Windows Server 2022 Data Center where the screen goes blank after a few seconds of idleness and then shows the login screen. Additionally, you mentioned that no domain policies are loaded and there is a log in Event Viewer regarding a task called UserTask-Roam that corresponds to the time of the log off.
To troubleshoot this issue, here are some steps you can try:
1. Disable the UserTask-Roam task: Since the UserTask-Roam task is triggering the log off, you can try disabling this task to see if it resolves the issue. Open Task Scheduler, navigate to Task Scheduler Library -> Microsoft -> Windows -> UserTask-Roam, and disable the task.
2. Power Plan settings: You mentioned that you've already changed the power plan settings, but it's worth double-checking them. Go to Power Options in Control Panel and make sure that the power plan settings are configured appropriately. You can try adjusting the "Turn off display" and "Put the computer to sleep" settings to a longer duration or set them to "Never" to prevent the screen from going blank.
3. Group Policy settings: Verify that there are no Group Policy settings in your domain that enforce the screen lock or log off behavior. Check with your network administrator to ensure that there are no policies applied that could be causing this issue.
4. Update display drivers: Outdated or incompatible display drivers can sometimes cause issues with screen blanking. Make sure you have the latest drivers for your display adapter installed. Update them if necessary, and then restart the server to apply the changes.
5. Check for conflicting software: If you have recently installed any third-party software that might interfere with the screen saver or power settings, try uninstalling or disabling it temporarily to see if it resolves the issue.
6. Disable screensaver: Even if you have changed the screensaver settings, try disabling the screensaver completely to rule out any conflicts. Right-click on the desktop, select Personalize, go to Lock screen, and set the "Screen timeout settings" to a longer duration or "Never."
If the issue persists after trying these steps, it might be worth consulting with Microsoft Support or your network administrator to further investigate the problem. They will be able to analyze event logs and provide more targeted assistance.
Remember to back up your system before making any significant changes and ensure that you are working within your organization's IT policies and procedures.