Note: I’m not sure if the TuneIn integration still works or is completely broken meanwhile (there was a reason for Roon Labs to create their own Radio Library after all). Users may be better off using a working and tested stream URL instead of the TuneIn integration.
Searching for stream URLs might be beyond what a common user is willing to invest, so please post request to add radio stations to Roon into the respective forum category #live-radio.
As @BlackJack says, TuneIn integration can be problematic with a few streams of a certain format. It usually works, but not always. The radio curators are always happy to help and add such stations to the Room database where possible.
In your cases, I have added
Dance One Radio Costa Del Mar - Deep House Deep House Ibiza
Searching with the magnifying glass is the easiest way to find these.
Unfortunately, I haven’t been able to find a stream for USA Dance Radio that Roon will accept. I’ll inform the Devs about that one.