According to the documentary "One Strange Rock", which I admit I have not fact checked, your statement is absolutely false. The documentary claims 100% of the oxygen produced by the Amazon rain forest is used up by the animals that live in it.
EDIT:
Also this PBS article backups the claim. https://www.pbs.org/newshour/science/no-the-amazon-fires-won...
"Forest plants produce lots of oxygen, and forest microbes consume a lot of oxygen. As a result, net production of oxygen by forests – and indeed, all land plants – is very close to zero."
Forests do sequester carbon for a period, although most of it is released again in fires and decomposition (chemically just a slow fire.)
But the point is that a forest locks up a lot of carbon compared to cleared grazing or cropland.
Trees sequester carbon. They also return that carbon to the atmosphere eventually, but as long as they're replaced by new trees, that's fine. That's not what's happening in the Amazon.
From a carbon perspective forests for timber are even better because then we keep several generations of trees worth of carbon locked up in our structures. It's also an easier sell because that has real economic value.
From a biodiversity perspective it's not as good to have monoculture crops of any kind, including trees.