"Also, I am told a constant issue with pills is dosage is deeply uncertain, hence the MDMA deaths issue at Australian festivals"

I'll admit I haven't kept up with the research since I stopped going to house (now known as 'EDM' apparently) parties 20 years ago, but back then it was well known that 'mdma deaths' were actually people dying of dehydration or because of hearth issues due to combining mdma with other drugs. What's the status today? Do people actually die from mdma itself, or just in circumstances where mdma is involved?