OP here again. Maybe I’m not bringing this up in the right forum for feedback/feature requests. If not I apologize but I want to mention that in my Emby evaluation, I discovered a similar problem with one of their apps, specifically Roku. It had the same deinterlacing issue that the AppleTV app has with Plex. I brought it up on Emby’s community and their developers had it fixed and a beta version of their Roku app available within 48 hours.
It would be very nice if Plex’s dev team could look at fixing this core functionality.