I’ve got a couple of Zigbee plugs, all work well, except one I use for the washing machine. It randomly turns off. When I check the history in HA, it just says that it turns off, no source. My guess is that it trips, ie temporarily exceeds 10A. The plugs are rated 10A from Aliexpress.
By the math you are correct. I blew out some switches that were 10A, 120VAC peak, but somehow only rated for 600W continuous, resistive. Amazon doesn’t sell them anymore, but it would be printed on the housing if that’s the case. That’s why I was saying to look.
My switches might have been the “no neutral” variety, though those are a special kind of janky.