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):
https://support.roku.com/article/360057488733
Is my Roku device compatible?
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:
Device Model
Roku TV™ | Axxxx, Cxxxx, CxxGB, 7xxxx |
Roku Streambar™ | 9102 |
Roku Smart Soundbar | 9101, 9100 |
Roku Ultra | 4800, 4670, 4661, 4662, 4660, 4640 |
Roku Premiere | 4630, 4620, 3920 |
Roku Streaming Stick®+ | 3811, 3810 |
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.
