@Wayne-TP I use Legrand Niloé Step

Single with outside mirror - 8.5x8.5cm

Double with mirror - 15.7x8.5cm

When is a single hole the S210 or 20 fit with no problem, when its doble holes to fit 2 wall switch is a problem.

Im in Portugal but in general in Europe this is the common measures I think.

  @Wayne-TP Aqara just lunch in IFA24 the H2 Switch with 55mm, work with third party frames like mine dumb legrand..... Just nice....

  @jfilipelcarvalh 

Sockets adapted to European standards would be a great option. I would also like to replace it at home, but I will not install several sockets next to each other in place of the existing, old, non-smart sockets.

I use Berker ones, but I think the dimensions are standard for different manufacturers.

  @jfilipelcarvalh 

A single Tapo switch should have a maximum width of 70mm and would then fit the existing standard for the arrangement of flush-mounted boxes in multi-switch installations that are popular in Europe.