Opioid use is not inherently dangerous (indeed, long-term pharmaceutical-grade opioid use is remarkably safe does not cause organ damage, unlike alcohol). There are several actual circumstances where opioid use gets dangerous to life and they are:
1) Dosage/concentration uncertainty
2) Contamination of a lower strength opioid (say, morphine or heroin) with a much higher strength one (fentanyl or fentanyl analogues)
3) Poly-drug use -- such as combining opioids with benzos to exploit synergistic effects
When it comes to pharmaceutical-grade opioids, the doses are known and measured and there's no risk of contamination with unknown amounts of fentanyl analogues. Indeed, the mechanisms of drug prohibition actually incentivize the use of extremely high potency/volume opioids such as fentanyl.
The third issue, poly-drug use, also is a consequence of prohibition -- the prices of opioids in the black market are artificially inflated (if you don't have the requisite permission slip for the drugs, you need to invest in all sorts of countermeasures to avoid being put in a cage and your product seized), so users need to economize, and this sadly happens by combining benzos with opioids, which can lead to fatal respiratory depression. This is also a symptom of prohibition and is not inherent to opioid use.
There are definitely real harms involved with / caused by opioid use today -- but most of those are caused by (or greatly worsened by) opioid prohibition.