The court ruling of the Powley case established a very concrete method with which to determine the validity of both what qualifies as a rights-bearing Métis community, and who is a rights-bearing Métis.
While Self-identification as a Métis person is one of the key parts of establishing Métis identity, that self-identification cannot exist in a vacuum. As mentioned in the Powley case, that Métis identity must also accompany an ancestral connection to a recognized historical community, and also to acceptance as a Métis by a modern community that is a living, thriving community that collectively descends from that historical community.
While many Canadians have a measure of indigenous ancestry that blends with their European heritage, the thing they often lack and which keeps them from claiming rights as a Métis under s35 of the Constitution is the lack of a connection to a rights-bearing community. While it’s possible to look back in the annals of history and potentially find that your ancestors were part of a historical community, the question is this: does your “Métis” community actually still exist as a community? The thing is that unless that historical community of mixed-blood people you descend from has maintained some form of collective identity, quasi-cohesive mutual interdependence, or has been understood by outsiders to stand apart (and together) as a separate, indigenous community/entity from mainstream society, from historic times until present day, it is very unlikely that your community exists or that it can be proven in a way that would meet S35, or that would ever be legally recognized by Canada.
Just finding evidence of a historic community that included mixed-blood people is not enough, because communities can scatter and the members can wind up in various towns and cities, becoming assimilated and absorbed into mainstream society, which is what happened to most (all?) of the historical mixed-blood populations in eastern Canada. Just because online genealogical research makes it easy to search your family tree back to the 1600s where you might errantly find a distant Indian great grandmother who had mixed-blood children, does not mean that you have a connection to a historical community. Even more so, if you live in suburbia, a city, or a small town surrounded by non-indigenous Canadians the chances are that you, your parents, and several generations before you also lived, worked, and married with other non-indigenous Canadians. Your connection to that historical community was severed hundreds of years ago and a contemporary community never actually existed.
Sure, you can do your genealogy and find an ancient connection to an Indian ancestor; of course can declare yourself "Métis"; and certainly you can join one of the hundreds of newly formed “Métis communities” that have sprung up across Canada (from coast to coast to coast, as one fake Métis organization likes to say) and pretend to part of a community; but at the end of the day it is a meaningless declaration that doesn't fly in the real world of courts and government.
You aren’t Métis.