They need to start building differently.
During some 30/35+ waves of the last few summers we kept it below 23 degrees Celsius inside, even over many days of heat.
Until recently I lived in Ireland and people looked at me like I had 3 heads when I talked about air tightness, deciduous trees in front of south facing windows, and eaves/awnings - the idea that you might not _want_ as much light as possible baffled the dinosaurs in planning.
I hope the Netherlands is better but I still see an awful lot of windows with no protection from sunlight. Eaves are perfect (and deciduous trees) because you can angle them such that you get light in the winter but shade in the mid-day summer sun.