Hi, InfoTechRich!
Thanks for reaching out to Microsoft Community and posting your concerns regarding the screen brightness on your Surface Laptop 3. We understand it is important for you to be able to view movies without getting interrupted and we're sorry for the troubles
you have to go through. Thanks for taking the time to let us know about this and giving us the chance to help you out.
May we know if the same thing happens when you set the brightness level to 1 instead of 0?
Furthermore, you mentioned that only Netflix is affected here. Does it happen to other apps with a dark them? It is possible this is due to adaptive brightness. You may check this page to know more about Adaptive brightness and contrast on Surface devices. That page will help you out on what to do for cases like this.
If this answers your question, please let our Community know by marking this post as an answer. Otherwise, don't hesitate to respond to this thread if there’s anything else that needs to be addressed.
Kind regards,
Janette_Z