This is a mark of wisdom as I age. Previously I would have tried to soldier through, which wouldn't have worked, but I'd have been annoyed at it not working, even though I knew it wouldn't. Which was stupid.
Gonna have to move to a split schedule and only do stuff when it's cooler. Dunno if the rest of the household will allow this plan to work because it requires early afternoon napping, and they both suck at naps.