@supersook Nice job on your mirror!
The cost of one-way glass made us consider alternatives. As we recently remodeled our family room, we decided to mount the monitor inside a frame on the wall. I was able to route power and install an outlet inside the open wall and frame. We added a monitor arm and use the Dell monitor USB to power the Raspberry Pi 4. It is physically located on the wall by our kitchen, so it is convenient and easy to reference. It is also quite a conversation starter!
Scott