Hello there! This issue sounds like it could be related to the issue mentioned in this forum post:
forum.paradoxplaza.com
Could you please try the suggested workaround of changing your renderer to Vulkan, and then send an update here if it worked or not so we can continue the investigation?

Regarding Crashes on Windows 11's 24H2 Update
Hello everyone, Since the 24H2 Windows 11 update, some players have reported an issue where the entire computer freezes up either when starting Crusader Kings III, or during gameplay. We are working hard to find a solution to the issue but due...
Could you please try the suggested workaround of changing your renderer to Vulkan, and then send an update here if it worked or not so we can continue the investigation?