I have created a small plugin/channel for listening to radio.
Would it be possible on the ios app to long press the channel and then show like my two favourite radio stations (which i can chance with a config or something) ?
I tried searching for this but couldn't really find anything about this
Not sure what you mean by a "long press," but channel plugins cannot control the Plex player app. In Plex, the environment is completely controlled by the player apps, including media playback.
The channel plugin framework/API just allows you to create the various types of objects which are converted to XML documents that are read and used by each Plex player app to produce the various sections and media list types/metadata of your channel plugin as well as the individual media objects that the players use to decide how to play that media based on its codec support.