Dimmer I'm using. https://www.amazon.com/dp/B09DT173R1?ref=ppx_yo2ov_dt_b_product_details&th=1
Got it Wall <- Grangier voltage converter <- UK power strip <- US to UK Adapter <- Dimmer <- UK to US Adapter <- Lamp.
Been working well so far, you don't see a problem adding two adapters between the US plugged dimmer right?
https://www.amazon.com/dp/B072K3Y9KH?ref=ppx_yo2ov_dt_b_product_details&th=1 https://www.amazon.com/dp/B00N13DC9O?psc=1&ref=ppx_yo2ov_dt_b_product_details https://www.amazon.com/dp/B08FQZ9JJ6?psc=1&ref=ppx_yo2ov_dt_b_product_details (rest of the products)
The only US Zigbee dimmer plugs I've seen have been the GE and similar Enbrighten options.
Kasa does have a WiFi option that is actually rated for outdoor use. Treatlife makes single and dual receptacle outdoor WiFi versions as well.
Why Zwave rather than Wifi? You may be able to get wifi stuff that works with third party drivers. I think the Kasa/TP-Link should work, like this one - assuming that you have wifi at your outdoor plug