Quoting/paraphrasing for the group's understanding of fentanyl levels:
a.) 1-2ng/ml is used for analgesia, simple pain relief
b.) 10-20ng/ml is used for ANESTHESIA (i.e., going under for surgery where the doctor takes over your breathing for you by intubating you)
c.) 7 ng/ml or higher have been associated with fatalities.
Assuming those reports are accurate, Floyd was at 11 ng/ml, above the fatality threshold, and inside the anesthesia threshold.
For meth:
According to the literature:
"...Fatal levels of methamphetamine in blood to be in the range of 1.4 to 13 mg/L." (19 ng/ml = 0.019 mg/ML)
Add in COVID, THC, heart disease, none of this is a recipe for respiratory success.