The human population is ultimately independent of the biosphere through technology. And, in fact, some of the worst impacts on the biosphere are when we lean strongly on the biosphere to provide for us (for instance, cutting down forests to provide fuel and to clear land for inefficient farming practices vs using solar/wind/nuclear to provide energy while using dense and hyper-efficient farming practices).

Technology has huge returns to scale, and technology is how we're already able to handle our current population. So I'd say we are indeed better off with more people than less, particularly if we reduce agricultural land usage (which we're already doing) and switch to non-burning energy sources (so no fossil fuels and no biomass). An effectively vegan diet (either truly vegan or using lab-grown meat and dairy and eggs) would, by itself, drastically reduce both our reliance and impact on the biosphere. Vat-grown staples (think specialized microalgae) substituting for field-grown staples like corn or wheat or soy would further drastically reduce our impact.

The Earth ought to be a garden, but not one empty of people! And a human society without children would be some kind of dystopia.