I just got this setup myself.
I am using a Samsung Smartthings plug to monitor energy usage.
I have it setup to monitor anytime the washer goes over 11 watts (the minimum it uses during a cycle) and then it sets a "canAnnounce" boolean variable to true. Once the washer drops back down to 2 watts (its idle usage) it will do an announcement over my Alexas and then reset the canAnnounce variable back to false.
Planning to pair it with a door sensor so I can do periodic reminders until the door has been opened.
I'll repeat the whole setup for my dryer after the washer is finished.
I am assuming that they are not compatible with Zigbee/Zwave since they work over a wifi connection.
I do something similar to monitor by crawlspace dehumidifier. I bought this from Amazon, I used Webcore routines but Samsung also has built in smart apps to trigger based on energy and power. https://www.amazon.com/gp/product/B07PY4YPTF?ref=ppx_pt2_dt_b_prod_image
Yes! I don't know why I didn't think of that before.
I have SmartThings at home so it's easier for me to use https://smile.amazon.com/Samsung-SMARTPLUG-GP-WOU019BBAWU-Outlet-SmartThings/dp/B07PY4YPTF/ref=psdc_6396120011_t3_B08BLS9FR3?th=1 which is rated to 1800 watts
I use it in SmartThings so I'm not sure what will display in HA but I assume it's customizable.