I am planning to add an Android-to-Android functionality to the app sometime next year, but I don't have an Android TV to test it with yet. I'll definitely look into it, but it'll probably be a while before I can even get started.
I'm unfamiliar with scrcpy, but from a quick glance, it seems to require more technical know-how than mine. PopCast is made for ease of use for users with less technical experience.