Opioids ARE lethal and dangerous, the issue is street opioids are not reliable and pharmaceutical opioids are strictly controlled in pretty much every country.
As you said, many people accidentally overdose. Thousands every year, it's literally become a health crisis. I come from a relatively "normal" family. My parents are divorced and my family has a history of alcoholism, but I guess what I mean is that no one in my family is really considered homeless, lower class, marginalized, etc. Even then, I have two close relatives who died from opioid overdose. My maternal grandfather and one of my uncles.
The truth with opioids is that if you take the correct dose, you will reliably die. The issue is that when people illegally buy fentanyl, usually what they're actually buying is a product marketed as containing fentanyl. Where I live, most commonly what you will find is a brown rock/chunk sold as "down". Sometimes in drug testing they find that it doesn't even contain fentanyl but other things like xylazine and artificial sweeteners like mannitol.
If you have access to a reasonable amount of pharmaceutical IV fentanyl, then yeah it's a great method. But shooting up brown shit you bought off of some guy in a shady part of town? Yeah, not risking that lol. You have a very poor idea of what you're actually getting beyond just trust and going by what it's been marketed as.
