As mentioned, I think it's an improvement over the status quo in its current form already. If you think the "more ideal" version I drafted is too complex to implement until the next release or so I'd be in favour of your PR as is.

We could also set a deadline of a month or so and simply merge if neither of us found the motivation to work on it until then.

got it running with these envars atm lol:

 LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/nix/store/i8zj05aiw2qxcwjwfjvcy9dwz798w7wm-libxcb-1.16/lib:/nix/store/9z0smixinzbi23jr3zjs87gnq6s8r1y3-libX11-1.8.7/lib
LD_PRELOAD=/nix/store/jvjxynmkri8l0mzpi49l3b1741h7818k-obs-vkcapture-1.4.7/lib/libobs_glcapture.so

{
    "file_format_version": "1.1.2",
    "layer": {
        "name": "VK_LAYER_OBS_vkcapture_32",
        "type": "GLOBAL",
        "library_path": "/nix/store/jvjxynmkri8l0mzpi49l3b1741h7818k-obs-vkcapture-1.4.7/lib/libVkLayer_obs_vkcapture.so",
        "api_version": "1.3.280",
        "implementation_version": "1",
        "description": "OBS Linux game capture",
        "functions": {
            "vkNegotiateLoaderLayerInterfaceVersion": "OBS_Negotiate"
        },
        "enable_environment": {
            "OBS_VKCAPTURE": "1"
        },
        "disable_environment": {
            "DISABLE_OBS_VKCAPTURE": "1"
        }
    }
}