Currently in open beta, the developers are aiming for a system that tracks births, deaths, and migration as well as a 'detailed fertility model' that takes into account the terrain in your realm, available water sources, and other similar things. Sinews of War reworks Crusader Kings 3's economy, making it population-based. To access them, right-click on the game in your Steam library, select Properties, go to Betas, and pick your preferred version from the drop-down menu.
Should that happen, older versions of the game are available on separate beta branches, allowing you to continue playing modded games. Sometimes modders decide to drop projects or take longer to update them. Some of the mods featured below are works-in-progress that will receive more features as time passes, while others are 'full' versions that will be tweaked and updated to be playable under new patches. The inclusion of Steam Workshop support means that installing them particularly easy, simply requiring players who own CK3 to subscribe to whichever ones strike catch their eye.