maxImageCount is the maximum number of images the specified device supports for a swapchain created for the surface, and will be either 0, or greater than or equal to minImageCount. A value of 0 means that there is no limit on the number of images, though there may be limits related to the total amount of memory used by presentable images.
this is listed in the vulkan spec: https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VkSurfaceCapabilitiesKHR.html
maxImageCount is the maximum number of images the specified device supports for a swapchain created for the surface, and will be either 0, or greater than or equal to minImageCount. A value of 0 means that there is no limit on the number of images, though there may be limits related to the total amount of memory used by presentable images.