[TSiege]

Not necessarily, (or even according to climate models I’ve seen). The feedback the OP mentioned is because trees near the coasts catch rain that they then respirate back up and create an atmospheric river that moves inland and falls as rain thus continuing the cycle inward. This cycle is disrupted by deforestation and can stop during a state change where it turns into Savannah. Savannah's are much drier and don’t cycle through water like the rain forest would. We’ll also see abrupt changes in global climate which will lead to completely different global rainfall patterns than we know today. For example the Sahara desert will likely turn into grassland/forest (which has happened in the past). The rainforest being a holdover from the Eocene is news to me, but my understanding was that the climate of the Holocene that we are leaving had weather patterns that facilitated a positive feedback with the Amazon rainforest expansion. From my understanding a thriving Amazon also necessarily depended on a desert Sahara as they drive weather/nutrient patterns that helps the Amazon