For a 400 sq ft room aim for an ultrasonic diffuser that can push 70–100 ml/hour on high and has an 8–10 hour timer or a true intermittent mode; that combo keeps it quiet and consistent overnight. Nebulizing (waterless) units fill big rooms faster, but they’re usually louder and burn through oil, so ultrasonic is the safer bet for sleep. A directional nozzle or dual mist spout, placed 2–3 feet high and away from corners and helps the scent distribute evenly.
I'm with you on this pick. That barista oat blend actually stretches into fine, glossy microfoam on a basic wand, holds latte art, and stays stable in espresso instead of breaking. The flavor is balanced rather than sugary and the shelf stable format makes it easy to keep on hand. I had the same collapse with standard oats at home until I switched to it.