The only solution I see at this point is mass protest and starting to assassinate CEOs, shareholders, and boards of directors, in self defense
Historically, terrorism isn’t really a good way towards the elimination of capitalism. The creation of strong unions linked to communist parties (not in the “liberal democracy” sense of party, but in the communist sense) is a historically more proven way to fight against capitalist power structures. Unionise, create local dual power structures and mutual aid, join a militant communist party.
Overpopulation isn’t defined by how much people there are, but by the total amount of sustainably produced goods and services divided by the total population. Fewer people producing unsustainably would also be overpopulation. We need to transition to sustainability regardless of amount of people, reducing population only leads to slower decline, not to a stop of it.