It is, to say the least, highly questionable that it was a general belief in pre-Christian Scandinavia that Valhalla was or should be the main destination in the afterlife.

Odin was probably not the main god except for poets - ordinary people worshipped Thor, Frey or Tyr. We don´t know how common the believe in Ragnarök even was.

A lot of viking era graves indicate that they were constructed as if the grave was the eternal staying place of the deceased. Icelandic Sagas, probably influenced oral storytelling, indicates a believe that the deceased simply goes into some local mountain in the area (Helgafell, Lomagnupur etc).

The idea of the violent, constantly raiding viking who lived a warriors life hoping to die in battle to go to Valhalla is a literature phenonema. Pre-christian scandinavians mostly were farmers and hunters, and their seafaring was mostly about trading.

Christians were pretty hooked up the afterlife -. That was the big thing, the point of everything, and it was/is important to them to live their live dedicated to the right afterlife. We cannot, and dont really have any good reason to assume, that the afterlife was as important to vikings. They believed in an afterlife of course, but it was probably not as muche the focal point of their religous practices.