>>1424269>Carbon frame allow for fine tuning flex and stiffness in the frame while alu does not so much. Even with lots of suspension, compliance is going to affect the ride of the bike.it will but its totally secondary compared to the importance of frame compliance of a rigid bike, let alone a rigid bike with small tires that goes fast (=road bike), which is why carbon in mtb is a tradeoff of different proportions than in road cycling.
So in full suss mtb, carbon makes least of a difference out of all cycling genres (which doesnt mean you wont notice it but its comparably less important upgrade).