Let's say Canada removed French language rights, and Quebec demanded autonomy or independence as a democratic process. If US sided with Quebec while Russia armed Canada, and just denied without evidence/reality that Quebec's democratic will could be valid. If the situation progresses such that the US liberates Quebec, and Quebec chooses to join US, does an end of the war have to revert to Canadian control of Quebec?

If you go back to the start of the conflict, the removal of French language rights was an aggressive and unwelcoming act on the part of Canada. As was the refusal of autonomy or independence reaction to the instigation. The motives for the new hostility should be questioned including foreign power interference to create instability.

I would rather suicide bomb a crowd of Americans than accept defeat.

You would have already supported the side that hates Quebec. A perfectly sane response to hate is for you to be happy they are kicked out of your country. The less sane response is that those you hate can only be under the fascist control of your ruler, and you are volunteering to rabidly fulfill that fascism.