The question of unbiased sources! I don't think you can find them - in my opinion the best you can do is instead of looking for unbiased sources, look for original sources - first person accounts of events, of contact, of the period following contact, and so on.

Of course there are far more of these from a settler perspective than from a First Nations perspective, but they do exist from both sides, albeit not always in the form you might expect. Here's a list of types of sources that come to mind:

I'm a linguist so I often look at stories that have been gathered by other linguists - they often tell history from perspectives you don't get when people decide to record their history in English.

Old newspapers! One cool example is the Kamloops Wawa, a newspaper written in Chinook Wawa for a number of years, that includes many articles and stories written by and for First Nations people describing contact time periods.

Commissions - for example the McBride commission that went around BC looking at the reserve situation. Sure you're getting just one perspective (everything that people are upset about) but it's a good source on opinions.

The odd memoir. This is becoming a much more common thing. In my own research I've been relying on a lot of memoirs to gauge the impact of residential school on people. There are books from across Canada by elders who went through the schools as children. you might think of these as recent, but remember that for much of Canada, "contact" was something that basically happened in the last hundred years, and for some groups it was as late as the fifties.

you can also find letters from missionaries, from RCMP officers, from government officials, as well as memoirs and sometimes reports.

Settler Oral histories! I find these actually to be some of the most interesting things as they often go the farthest to flip some of the images you have. In the fifties a CBC Radio guy named Umbert Orchard travelled around BC interviewing old timers about their lives, often going back to the 1880s. I have listened to all of his interviews that I could get my hands on - many of the characters are multilingual, speak First Nations languages, were involved in promoting First Nations rights and land claims, and were also settlers. Their description of the strong social connections, interactions, and how society works really does show a different picture than we often get from the writings of the next generation who seem to have grown up in a far more fractured environment. There's often good recordings of First nations elders as well mixed in.

The easiest way to reduce bias in sources is to look at a lot of sources and make sure you are looking at different kinds of sources. As /u/Muskwatch recommends, primary sources are very valuable. But secondary and even tertiary sources can be very valuable too as are reviews. Every major North American journal that I read has reviews - read them. These include reviews of books, journal articles and technical reports.

The western portions of Canada were subject to some of earliest, high quality anthropology in North America because of research by Franz Boas and his students. Make sure you look at primary accounts. There is also very valuable information in syntheses and secondary accounts. The Smithsonian's series Handbook of North American Indians is dated now, but can provide a lot of good info. Synthetic prehistories or "anthropologies of...", like Ames and Maschner's People of the Northwest Coast: their archaeology and prehistory are great because they bring together disparate information and draw defendable conclusions from it.

Stay away from popular histories or anthropologies, they are often sensational and inaccurate. Finally, research the bias that is already evident. If you are interested in genocide, and there is no shortage of it in the new world, try Brendan Lindsay's Murder State: California's Native American Genocide, 1846-1873, here is a nice review.

Exercise your critical thinking. If something doesn't sound right, see if you can falsify it, either with contrary resources or your own logic. Finally, use forums like this where you can get responses from multiple people with differing perspectives.

tldr: read lots of sources, lots of different types of sources, treat them with some healthy skepticism and keep asking questions on sites like this.