Same here, interacting with people makes my performance on all sorts of mental tasks drop much faster. 5-6 hours of meetings, and worst case I don't want to do anything else, best case I still need to go for a walk and another 30 minutes on top of that before I'm back to average coding skill.
On the flip side, even for coding I don't love, I can usually grind out 9-10 hours at fairly high productivity; I usually won't because I have other priorities to balance but I can. If I find what I'm working on really interesting, I can do 12 hours at high productivity.
For work, I try to have 2 days a week where I put most of my meetings so that hopefully at least 1 or 2 days of the rest are high productivity.
On the flip side, even for coding I don't love, I can usually grind out 9-10 hours at fairly high productivity; I usually won't because I have other priorities to balance but I can. If I find what I'm working on really interesting, I can do 12 hours at high productivity.
For work, I try to have 2 days a week where I put most of my meetings so that hopefully at least 1 or 2 days of the rest are high productivity.