Coincidentally I am reading Children of Ash and Elm: A History of the Vikings, and there is a chapter on Viking burial practices and similarly archaeologists are left to do a lot of guesswork and hypothesizing despite these being only 1000-1200 years old since there’s quite a bit of variation and all of the written records comes via contemporary visitors from much different cultures or hundreds of years later via the Christian tinted lenses of transcribers who may have been conquered or invaded by Vikings of various sorts. There’s a lot of space for fictionalization that could fit the evidence like this novel - à la Vinland Saga manga.