Hey there @KTP_Ahlai_Enzo! Welcome to the community! So static lighting is so performant because it’s calculated before runtime and baked into maps to be loaded at once. This basically means that it can’t move or change in most meaningful ways because then those maps would have to be re-baked, which would mean you would just use another light mobility in most cases.
One workaround I’ve seen (though I can’t attest to exactly how much performance because I have never personally done it) is that users will use a two light system. One static at the lowest intensity of the flicker with shadows on and one Movable in the same location with very low light attenuation with shadows and other features disabled for performance. This can get you a dynamic flickering without having to pay the shadow performance cost, but it will look worse than just using a movable light with shadows.