@ghostman90215 It is actually a way. I am doing it myself, for broadcasting live tv over a fixed UHF/VHF frequency (old school tv). So the way to do it is to connect your projector or any machine to your computer, then:
-Right-Click you desktop and go to "Display Settings" Or "Screen Resolution"
- Check if you have 2 monitors connected and change "Duplicate these displays" to "Extend these displays", and make sure that the monitor with the number one is your monitor, not your projector. You can check by clicking on the "Identify" button.
-Go to obs and right click => Output to projector (fullscreen) and choose your projector.
Hope I helped you and sorry for the late reply, I just found it the other day.