https://ourworldindata.org/us-life-expectancy-low

The life expectancy in the US is also dragged down by other factors. The US is a huge outlier in several other aspects:

• Higher death rates from smoking, obesity, homicides, opioid overdoses, suicides, road accidents, and infant deaths, compared to other countries.
• Additionally, deeper poverty, economic inequality.

It could just be that the US has way more vices per capita than other countries.