Answer: yes, you will increase your insulation performance.
It is quite possible to accumulate several layers of insulation. In some cases, the installation of several layers of insulation is even recommended. The accumulation of layers increases the mass of your insulation, which is a key factor in the race to save energy. The superposition of the layers makes it possible in particular to cut all the thermal bridges. Be careful however, the cumulative layers of insulation cannot adapt to all structures. The increase in the insulating mass necessarily requires more space, so you need the space necessary to accommodate all these materials. You too, send us your brico question