> I’m interested in how they combine AI with EEG for better sleep tracking.

I'm not super well versed in how this works technically. My understanding is that even with raw EEG, accelerometer, and heart rate data it's not a straightforward problem to figure out what stage of sleep you're in. From the consumer side, I've just noticed a few patches they push down to my headband with "improved sleep tracking" in the changelog.

> have you experienced any discomfort from wearing a headband full of tech all night?

Nope. I was already wearing ear plugs and an eye mask, so the headband is a barely noticeable addition, even when side-sleeping.