If you want the lightmap to be really blurry, make the lights static instead of stationary (or tick on area shadows, but if you really want that old lighting look you should avoid any stationary or dynamic lights). You can also kill highlights on materials by setting the specular to 0. If you really want those black shadows, in the lightmass settings for the map set the amount of bounces to 0.
And you’re going to want that post process volume so you can actually turn -off- features that will be on by default like SSAO, SSR, TAA, vignetting, bloom, lens flares, and eye adaptation.