I use Synfonium in my car via Bluetooth from my smartphone (Samsung Galaxy A54). I have enabled Bluetooth auto play in Synfonium, but whether the music starts automatically or not seems to be somewhat variable.
I am not certain of what appears to trigger this, but it does seem that, if I have not used the phone for any other purpose between Synfonium uses, then it seems to work OK. However, if I have been using other phone apps in between Synfonium starts then there is an issue, in that, the car display shows the ‘now playing’ info accurately, showing a ‘pause’ icon, ie. it thinks the player is playing, but it isn’t. When I check the phone, Synfonium is displaying a ‘play’ icon because it is not playing.
As I say, I am not convinced that I can consistently reproduce this activity, but it is extremely irritating, and if it cannot be rectified then it is certainly a deal-breaker when it comes to going ahead with a purchase.
There’s 2 days of logs, without details of the times where it failed it’s hard to tell anything.
All I can easily see is that your device kills the app a lot for no reason, see https://dontkillmyapp.com/ for how to prevent your device from not respecting Android standards.