I avoid adding any humidifier to my supplemental O2 system as I feel it’s a way to increase bacteria levels and I know I hate extra cleaning & sanitizing.

I have only seen humidifiers added to continuous flow machines and they are supposed to be cleaned/sanitized regularly.

I have a continuous flow concentrator for sleep and the G5 only for activity and altitudes. I have difficulty sleeping with the G5 because it only delivers pulse. I sleep with 2 liters/min continuous flow instead and it works well.

For the dry nose, you can use a water-based gel. For the dry throat, might it help to tape your mouth shut when you sleep, using a mild adhesive tape? My daughter does that and feels it helps her.