Function vk_mem_alloc::ffi::vmaGetPhysicalDeviceProperties

pub unsafe extern "C" fn vmaGetPhysicalDeviceProperties(
    allocator: VmaAllocator,
    ppPhysicalDeviceProperties: *mut *const PhysicalDeviceProperties
)

PhysicalDeviceProperties are fetched from physicalDevice by the allocator. You can access it here, without fetching it again on your own.