Smart switches for 2, 3 switches tougether

Hello Everyone,

I would like to change some of my switches to a smart one, where I can not change the bulb.
I was thinking about the SONOFF but they are too big.
May some of you were in the same situation and found a good solution for this situation.

In some places I have switch and under there is a socket you know.
This is a simple EU standard.

I could be some switch under the old switch what I can link to hassio, or a totally new switch.

So do you have any idea to solve this?

Here some pictures:


Thanks!