Why Roku needs mirroring, and what that costs you
Roku operates a closed channel store with no sideloading, which means there is no route to install a third-party IPTV app on the device at all. This is not a limitation of any particular service — it is a platform decision, and it applies to every independent provider equally. Anyone advertising a native Roku app for an independent IPTV service is describing something that does not exist.
So the working route is screen mirroring from a phone, tablet or PC that runs the app, with the Roku acting purely as a display. Enable it under Settings, System, Screen mirroring, and set the mode to Prompt or Always allow. Quality then depends on the mirroring link rather than on the Roku: your phone decodes the stream, re-encodes it, and sends it across your Wi-Fi, which roughly doubles the demands on the network.
The practical consequences are worth knowing before you rely on it. Battery drains quickly on the mirroring device, an incoming call can interrupt playback, and there is a delay of a second or two that makes it a poor choice for live sport you are also following on social media.
Getting the best out of a mirrored picture
Mirror from an Android device or a Windows laptop if you have the choice. iPhones and iPads cannot mirror to Roku natively — AirPlay support on Roku covers Apple's own protocol for photos and some video apps, but not reliable full-screen mirroring of an arbitrary player — so an iPhone route needs a third-party helper app and is the least stable of the options.
Put the mirroring device on 5 GHz Wi-Fi and keep it in the same room as the Roku. Mirroring is far more sensitive to distance than ordinary streaming, because it is a continuous real-time encode rather than a buffered download that can absorb a hiccup.
If you watch live television daily, the honest advice is that a cheap Fire TV stick or Android TV box in the same HDMI port will give a better experience than mirroring ever will, and costs less than a couple of months of subscription. We would rather say that than sell you a setup you end up resenting.