Just an FYI really if other S10 users are having issues. It's not ARUnchained but the phone itself and bug with the way it pairs.
Lately I have been having an issue connecting. S10 HDMI. Sometimes it connects right up. Most of the time it hangs at 50% for quite awhile, 10 - 15 minutes sometimes. I tried the channel work around but didn't have much luck.
Do you mind looking at the attached log off it happening to see if you can set anything. I have been using arunchained for years in various Galaxy phones and haven't had a problem until now. It seemed to work fine when I first got my S10 and even reported it working here but something has gone wrong.
I did try resetting the app and even the radio itself.