Over all linux is awesome. However the sound system has been a problem on and off for a very long time. I don't really like pulse audio, but at least now we seem to have converged to one system and we can fix it over time.
One reason i use slack it that over the years it has been the only one to get sound right out of the box. Currently with pulse audio i run different sound streams at different levels to blue tooth, ear phones the speakers and a USB headset without issues.
But i still get the odd issue with Chrome hogging a device and not giving it up. However it is weird to have a NPE and a crash. Typically sound just wont work.
Have you tried without sound enabled. or sound off?