i think there’s a different “sweet spot” for everyone. i agree, doing 3h of productivity in 3h is hard enough, but i wouldn’t necessarily need to stretch it over 8h, i’d do fine with 5-6h. my last work hours tend to be the most unproductive ones anyway
my grandad can stand and talk for hours, that doesn’t mean his ramblings would make any sense, or that he could run our country