The instant Alberta secedes from Canada, the Indigenous would secede all unceded Treaty land from the independent Alberta. Which includes all of the tar sands, the source of Alberta's wealth.
Canada might not be willing to fight, but the Indigenous probably are.
> but the Indigenous probably are
None of this matters in this context. The indiginous people literally do not matter. It's bad, but it's just how it is when white Europeans start fighting over land in North America. We have 3 centuries of evidence.