(not OP) I'm no libertarian, but there's another way... monitored legalization! Admittedly, the locations of legalization success stories haven't generally had to contend with fentanyl. But I'm also not convinced by the argument that we should hang anyone with drugs on them. The fact that Singapore continues to execute prisoners shows that the fabric of Singaporean society is still being destroyed by drugs, or alternatively that the fabric of society is damaged enough by other causes that people are being driven to deal in drugs.
As someone living in a country where executions are illegal, I do not wish to see the impact of substance abuse exploited to justify the reintroduction of a practice that many of my fellow citizens consider barbaric.