I've pushed the move of swapchains/surface objects to https://gitlab.winehq.org/rbernon/wine/-/commits/wip/vulkan-objects, it would be helpful to have it upstream, or at least to agree on a plan, to rebase various Proton hacks on top.
I'm also looking into future paths to implement compositing, and having these wrappers (and later the VkDeviceMemory wrappers) in win32u seems useful. For shared resources, in order to implement the D3DKMT integration, we'll also likely need to wrap semaphores and fences, perhaps images and buffers (although that could be impactful performance-wise, and maybe we can just cache their create infos).