Most of my info comes from this post: https://www.collabora.com/news-and-blog/news-and-events/nvk-holiday-update.html
Performance boost isn't Vulkan-only. GSP reclocking benefits everything, Vulkan or otherwise. NVK is strictly a Vulkan driver, but Zink, which implements OpenGL on top of Vulkan, currently has better performance when used with NVK than the old OpenGL driver, so it can also be considered to improve performance across the board. Right now it's a pain to set up tho, since it's not ready for prime time quite yet. Can't really help you there, since I don't have Nvidia hardware. The Collabora guys say they want it to be in Fedora 40, which means NVK should start showing up in distros by next April. It'll probably be much easier to test things out by then.