I haven't yet seen my exact question asked (but many close), so forgive me if it has been already answered. is it possible to duplicate an android display on a non pc, stand alone, powered display ? and if so, how ? and are there multiple ways ? thx
There are various ways to accomplish this (assuming that your display has an HDMI input), you can use a Chromecast device or directly connect your phone using an HDMI cable (again assuming that your phone supports that.)
If the above options are not suitable for you, you can make use of a raspberry pi to act as a bridge between your phone and the display.
Please provide more details about your phone and the display.