It is good to note that sleep tracking is one of those things that is kind of a hand-wavy thing right now And it has actually shown to increase anxiety when using sleep trackers when people get less than great sleep, and can make things worse when the algorithm incorrectly estates quality (which all if those proprietary apps do instead of just tracking sleep state).

There is also the issue of comparing with eeg which the head unit that the qualified scientist is also not completely accurate, it is just the best that is readily available.

Sorry that I can't be helpful, but I dived into it a while ago and what came out of my search was pretty much that it is not reliable and people pay way too much attention to it when they should pay attention to how they feel.