I've tracked sleep using a number of devices and algorithms and I haven't found a single one that regularly aligns with what and how I feel. I know it's tracking real data, but the conclusions feel completely made up. What are other people's experience -- especially from those who are more bullish about sleep tracking?
it's a lot of work, but something you could do is track how you feel (manually or some other way) and do a similar statistical analysis. chess elo was just convenient and aligned for me.
I do have an iOS shortcut that tracks my mood with janky emojis. I use it at least once daily.