Buying tracts of land is ok, but it is not as liquid as bitcoin and gold. It takes a lot of time to find a seller and eventually sell the land title. I think the same can be said of flipping houses, unless you are a very good broker. But no doubt about real estate being a good investment because it appreciates in value over time, although not in the same phase as the rise in price of bitcoin.
Keep in mind that most perfectly good residential land in the West is banned by law or regulation from real estate development. The purpose of these laws and regulations is to prop up the value of existing real estate. Real estate is a big part of the support for the dollar-based system.
What the law gives, it can take away. When the financial system comes crashing down, one of the options open to the elites will be to back their money with land. This happened in the 1920s when the Weimar Republic of Germany issued a land-backed 'Rentenmark' to stop the hyper-inflation of the old mark, successfully. It will greatly increase the value of the government's land holdings, used to back the dollar, if it deregulates at that point (the reason being a love of free markets!)