The Apple Watch records my wrist temp not as I sleep, but when I turn off sleep focus

Just come to my attention that using your Apple Watch to measure your wrist temperature for apps like Natural Cycles requires you to turn off sleep focus as soon as you wake up. That’s because it measures your temperature when you turn off sleep focus, not as you’re waking up. Which seems stupid because the watch is able to tell when you wake up, so why doesn’t it just measure then? I snooze a lot so I guess all of my temperature readings are incorrect for as long as I’ve been using my watch.

[Re-Titled by Moderator]