We bought Roku TV Onn as it shows its a smartTV but I guess it wasnt that smart at all, it missing the Airplay feature. When I called the Onn customer service they would say it will be able soon but when... this is false advertising as the item isn’t fully providing features
Actually, mirroring turns "Smart" devices into "Dumb" ones, since it just turns them into pure data conduits to the TV/AVR (the phone/tablet acts as the "Smart" device, running the app and controlling the stream/playback)
Regardless, not all Roku players/Roku TVs support AirPlay (as a simple qualification test, the TV must be at least 4K HDR capable - a 32" 720p TV is never going to get AirPlay support):
To determine if you can use AirPlay and HomeKit with your Roku device, you need to know the software version and device model. To find this information, go to the home screen and select Settings > System > About.
The Roku devices listed below support streaming with AirPlay 2:
Axxxx, Cxxxx, CxxGB, 7xxxx
Roku Smart Soundbar
4800, 4670, 4661, 4662, 4660, 4640
4630, 4620, 3920
Roku Streaming Stick®+
To use AirPlay and HomeKit, your compatible Roku device must be running Roku OS 9.4 or higher. Your Roku device checks for an update every 24-36 hours or you can manually check for a software update if necessary.