I think the environmental impact can be limited:

• Highest demand peaks correlate with highest solar panel output, which would be hard to use or store otherwise. Especially nice when private, local panels are available.
• Some also work as a heat pump in reverse for highly efficient heating in winter.

Buildings need to integrate centralized cooling and district cooling much more.

If you are getting a heat pump then your impact on the climate will probably be better than your current radiator configuration. Especially as more renewables are brought online.

Sure that helps, still not enough when it's 35°C or more outside every day for a week and doesn't cool down further than 25°C outside at dawn.

My apartment is under the roof. It's well insulated but if the heat lasts longer than 3 days, it becomes unbearable. Heat soaked in, nothing we can do about it at this point.

That is because your house is well insulated.

In Belgium, we are living in a small house with roof insulation while renovating the main house.

The small house gets up to 32 degrees inside when it is 34 outside as it has little thermal mass and is not sealed as it is an old stone atelier. We have to sleep in 30+ heat regularly during heat waves.

Main house is better insulated. We resorted to blankets over the southern windows and it is around 26 inside without us living in it at all (windows open at night and shut during the day). When we shift to moving there, it will be warmer. We would have to spend 45 000€ to insulate the walls + 10 000€ for roll shutters. Heat pump is the next best option coming in at a small fraction of that.