Canada

To cool down housing, we need to quit the insane way we build car centric cities that results into either too little housing supply or too much hyper-densification. Each Canadian city needs to become more like Montreal: triplexes and other Xplexes everywhere. Added benefit: cheaper infrastructure costs, more resilient to climate change.

If they continue increasing, that again ruins affordability by increasing mortgage costs, which is the biggest expense for majority of people.

This is not quite true. Yes for the ones that have significant mortgages left and have signed / renewed recently. But that's likely not most people. For new mortgages that start in the high interest climate, the overall cost will be similar to the typical one as prices are already lower. For the whole of Ontario, there are ~200K real estate transactions per year. Over the span of 5 years, that's 1M. While inflation affects everything and everyone, outaized mortgage costs due to the affect a minority of the households.