Summary

This adapter is designed to convert a standard light switch into a smart one, while maintaining the traditional design.

The depth of the mounting box should be at least 5 cm.
To power the smart switch, both the phase and neutral wires should be brought to the box. Neither the mounting box nor the wall should shield the WiFi signal.
To assemble the adapter, you will need: 2 screws M3x8, 4 screws M3x20, 1 screw M3x18, 1 screw M3x22 (M3x20 can be used, but it is short).
All screws must be with a hidden head.
You will also need a key, frame and base plate from a standard wall switch as a donor.

I tested it on a switch marked "Vilma", but it should fit most EU standard switches.

Switch: https://a.aliexpress.com/_EQkx5NA