can oura ring explain persistent brain fog in controlled sleep apnea?

[photonut]

I am new to the forum, so please forgive me if this topic was discussed previously.

I have central sleep apnea which is incredibly well controlled (AHI 0-.2)
I have been using an ASV airsnese 10 for over 4 years. I also has a Contec pulse oximeter.
My SpO2 averages 92. During short occasional (5 second) episodes of mask leak, the SpO2 sometime drops down as low as 82
I purchased an Oura ring 4 months ago because of frequent brian fog/daytime tiredness even with 9-10 hours of sleep.
I was surprised to learn a few things with the ring:
1) my actual sleep time, according to the ring, is typically 1 1/2 to 2 hours less that my actual time in bed (perhaps the ring may not discern very light sleep from being awake, as I don't perceive I am actually awake for up to 2 hours a night!)
2) I am getting 1 hour or less deep sleep on most nights and 1 1/2 hours of REM. On these days I will typically have brain fog and feel tired, especially later in the day.
3) On days when I have full energy, I am getting 1 1/2 hours of deep and up to 2 hours of REM. Unfortunately these days are fall less frequent!

Do others find the Aura ring data correlates brain fog with length of deep sleep or REM sleep, even with excellent control of AHI?