Ban firms from owning more than 2 private residences.

They'll just open shell companies. Corporate participation in the housing market is morally wrong, and one of the biggest blunders in the justice system of the USA. It is an erosion of democracy. Housing is a fundamental human right. The vast majority of land is unoccupied, and that which is fit for occupation is not adequately zoned to compensate for the needs of people. The entire housing market is an inflation scam. There is absolutely no reason for houses to cost so much, especially considering they are made of toothpicks and papier-mâché with no attempt made to make them efficient or sustainable at scale.