What would really be nice is that if they actually update the app, they would give it android auto functionality 

I know, I've sideloaded apps into several phones and tablets over the years. Android 14 has told me no with several apps. I really wish XiiaLive would get an update so it'll work on newer phones. It's still my favorite music app and I even purchased the pro version years ago. Now I'm stuck using TuneIn and it's awful compared to it. But I really don't have any other options. 

Ive tried several, including the one you suggested. The app hasn't been updated in over 6 years, I'm honestly surprised it worked on my S22 for as long as it did. The S24 appears to be a no go. I've added a picture of the error message 

A file I downloaded from a website. I even tried to download previous versions of the app. I can download them no problem, but the phone just won't let it install. Probably has to do with the app not actually being updated in years. 

tried that many times. It won't install on the phone, when I try it just says "this app isn't compatible with the device"