Sorry, but it doesn't make sense to compare the Steam numbers of Shadows and Valhalla, or any other Ubisoft game. Shadows is the first Ubisoft game in a long time to be released on Steam on day one, they just changed their release policy. Valhalla, for example, took 24 extra months to launch on Steam, by which time most AC fans had already played it. Before that, it was available on other platforms like Epic, Ubi+, etc. Ubisoft itself said a few weeks ago that Shadows' sales numbers were behind Valhalla's.