Does anyone have a recommendation for a surface-mounted (not wall-mounted) smart EU socket that works with HA? So not the adapter you stick into an existing socket, and not a socket that you need to mount inside the wall.
It needs to have enough watts/ampers to handle a washing machine. Power consumption sensors are a must have, that is the main reason I need it. Preferably Zigbee, alternatively WiFi.
You should be able to get a empty box to mount a wall socket 80/86 on top of your wall instead of inside. Every random electronic store should sell them.
Now I feels stupid 
Haven’t though of that. Still though, I would prefer a finished thing, since the box and some random zigbee socket might not be exactly the same dimension, so it doesn’t stick out, or fall in, a little. But yeah, if there are none, I’ll just get an empty box.
I think in EU the stabdard is ether 80mm or 86mm square for outlets and wall switches.
For example you can then buy the outlet you want with the same dimension - for wall switch I use the sonoff m5 which is available in both 80 an 86mm. They are wifi and support esphome (essential for me nowadays after bad mileage with zigbee products). I expect sonoff also to sell outlets but never looked them up because of a lack of a use case.
Just keep one thing in mind: big loads like washing machines (specially with motors!) can put big stress on relays - if you don’t have a use case for switching the outlet for your washing machine just avoid it! Instead go with a non contact measurement solution if you only need power meter functions.