Hello @Nightcraxler ,
Thank you so much for posting here.
According to my experience, we could configure screensaver via GPO directly.
If we would like to force specific screen saver, enter the name of the file that contains the screen saver.
Please note that the screen saver should be stored on the computers locally.
If we set up the policy via registry, it will not change the GPO correspondingly. It is suggested that we could configure the GPO directly and then it will change the corresponding registry values.
For any question, please feel free to contact us.
Best regards,
Hannah Xiong