It does look like powdery mildew: https://www.gardeningknowhow.com/houseplants/hpgen/powdery-mildew-treatment.htm

I'm not going to recommend, as they say to, pinch off the leaves. Those leaves look perfectly healthy and PM isn't what I'd call a severe illness (it's common on a lot of plants and easy to treat). You can try the spray they recommend there-- 1 gallon water, 1 tbsp baking soda, 1/2 tsp liquid soap (or detergent).

In this case, I'm actually OK with either soap or detergent as we're trying to pH shift the surface of the leaf to kill the fungus, which doesn't like alkaline conditions. The baking soda is trying to do that as well as kill the fungus with a bit of sodium. Baking soda's also been shown to spark a reaction in the plant to help fight fungal infections for a few weeks.

This mix is one I've seen recommended for other plants, and I've tried it myself. It does work. You can also gently (very, VERY gently) rub it on the leaf to remove the worst of the PM, but be careful not to damage the leaf at all, it's been through enough.

Add horticultural oil if you want, but that's overkill in this case.

Severe cases can be treated with an antifungal but again, that's usually overkill. Where necessary, something like Daconil is usually more than enough.

one of the ways to prevent PM is to insure or increase air movement around the plant ...

ken