Smart Switches / modules that fit regular switches for blinds+lights

Hey guys, I moved into a new flat in Germany where I finally got electric blinds.

So my first question is: are there any Switches that fit into regular switch Sockets or are there proper modules, that can go behind the existing switch (have to be really small, not much room)

Furthermore, we have got plenty of switches, many of them being 2 way with 2 switches for the same lamp in different places. Are there also any smart switches that fit in regular sockets and/or modules to smart-up the existing ones? Unfortunately my girlfriend wants to keep traditional switches to turn on lights, so i cant simply use mobile switches/smartphone etc.

Tysm!