The Giant Revolt Advanced is not low end carbon. I've been riding one for just over a year and it's been joy & smiles to ride. Super fun on gravel & off-road whether you're bike packing or racing. I've done both and with the right tires it's not bad on pavement either.
Re: Carbon vs aluminum, I've owned a Giant Defy in both AL and CF. Same wheels, tires, components. The CF was barely 1lb lighter so no huge difference there. But the difference in ride quality was noticeable. CF has less buzz on chip seal & feels smoother.