There’s definitely a significant rise in excess deaths among 25-44 year olds coinciding with the Delta peak in August/September.
Something interesting though: In the Covid “valley” of June/July, when Covid-related deaths were at a record low nationally, 25-44 year olds still had a ~35% increase in excess deaths. I’d expect a drop in excess deaths close to prepandemic levels if they were being driven mainly by (short-term) Covid effects during that time. It seems like the baseline death rate increased independently of number of active Covid cases.
Covid deaths were accompanied by a steady increase in overdose deaths starting in early 2019 (https://www.cdc.gov/nchs/nvss/vsrr/drug-overdose-data.htm), rising from from 68k to 97k over the course of the pandemic.
I don’t have time at the moment to do the math, but I’d suspect most of the increase we’ve seen in the past year is due to Covid, but with the increase in overdoses and other causes contributing much than noise since 2019. This could explain the higher death rate that persisted throughout the summer.