Is cacao production unsustainable? It seems the problem is the oligopolistic and exploitative price setting architecture for cacao. Pay farmers more, and supply will increase.
One of the alt-chocolate alternatives mentioned here involve palm oil, one of the most environmentally destructive ingredients on the planet.
I don't think beyond meat is an example to follow. It is ultra-processed fake food ruinous of health, and rightly - at least in the UK - now has an aura of ill-health surrounding it. Better to just make yourself a burger with healthy whole foods, like lentils, mushrooms, chickpeas.