So your choices are, put up with it, with potential health problems for older/infirm people, rebuild to suit the new normal, or add an AC which hopefully is running from renewables and not contributing to the problem.

There is no easy solution.

I'm in Brisbane, and our climate is starting to move from northern subtropical to tropical. Most of the older houses are built for heat, but they are not built to deal with cyclones and extreme summer storms. Most of the new houses are not even built for heat, being designs that are popular in Sydney and Melbourne. Actually considering Sydney and Melbourne can get some stinking hot summers they are not even really built for that. Upshot is that most new houses are unliveable without AC, and this is in a country that has always had extremes of heat.