Classic Controls? The PS2 and 3 controllers had pressure sensitive face buttons used for aiming, shooting and lowering the gun. One of the things that the PS Vita and Switch remake could never properly replicate. I doubt this will be handled well in Delta.
You can also just unequip the gun before firing, but that breaks immersion. If I recall correctly, the XM16 and AK47 became essentially unusable because a soft press aims and hard press fires. But on the Vita the gun always instantly fires if you try to aim it.