Fr4nKB Today it seems that the charging limit worked propperly without emiting any sound (I was using ear(2) while that happened, no idea if that has any implication on the behaviour). Will check if the low battery works and come back to give more feedback. DND is off in my case.
In regards to the low battery widget, it keeps the background black on my phone, not sure if it was resolve. I checker if my app is updated, and it is update to this date.
Hope this can help! Thank you for your work! 🙂