I'm working on a native macOS app. I need to test some multi-monitor issues. When I'm at home I use AirPlay to my TV to test multi-monitor issues. But, when I'm at a cafe or co-working space if I could AirPlay to my iPhone then I could continue to work on multi-monitor issues.
I suspect people might suggest Air Display but I'm not sure it lets me display to iPhone and reviews are very poor.
Ideally I'd just like "AirPlay to iPhone" to show up as an option on my Mac.