This issues has been many, same with another device Galaxy Note FE, S9 & S9+ most issues come after updating to Oreo, i have same problem too, i has try searching and trying any sollution on the web, nothing all can't solved, last day so i visit to service center and CS has told me it's 100% hardware issues, i have wait for 2 hour's and done, cos my device under warranty samsung has replace board with new one free of charge. Wish that help you.
This issues has been fixed by Samsung Service Center, today i send my phone to SSC and their said it's 100% Hardware fault, cos my phone still warranty Samsung has replace my Board with new one and fixed the problem and no charge, it's free. hope this can solve you too.
