The 3am part was just a random picked time. But interesting to know, thanks for sharing! I had some stress related sleeping issues about a year ago, that’s why I started with proactively provoking morning cortisol spikes and preventing them in the evenings which definitely helped. At that time I went through some personal challenges, so it made sense

Second this

Have the same pattern, issue is cortisol/stress, not sounds / etc that happen precisely at night

Built simular things tonwhat Op did (thoug using Oura for sleep tracking, not Garmin)

Result: no statistically significant variations in sounds, CO2 normal etc. Cortisol is what doctors/AI told me first