The Earth would be better off without humans. Fact. But there would be no way to un-do the havoc and chaos humans have caused. For example, if one person caught a disease, and spread it to the rest of humanity within a week, and every human died, all the impacts on the earth humans have would stop. There would be no more global warming, polloution, deforestation, oil spills and poaching. They would all stop. But the effects wouldn’t be reversed. So, really, the Earth would be better off if humans had NEVER exsisted. Here’s the thing, though. Because of evoloution, humans were always GOING to exist. The Earth is doomed, and was always going to be doomed. The sun is going to die eventually. The Earth will freeze and without the Sun to orbit around, it’ll drift through space aimlessly until it comes to another galaxy with a sun. It’ll thaw out, bacteria will evolve into insects and then into mammals, and fish and birds, and the whole damn cycle will start again.
Basically, we’re doomed. We are always going to be doomed. We always WERE going to be doomed. Just sit back and enjoy the ride.