Russian air defense is multi layered and relatively strong, so one of Ukraine's main strategies so far has been just to overwhelm them with volume. You want mass volume cheap and cheerful, not expensive ones, unless for the occasional strategic target.

Ukraine only has limited number of more capable missiles/drones like Flamingo FP-5 and Neptune, although now the FP-7 is about to hit volume production, followed by the FP-9, as well as Europe-supplied missile and anti-missile systems, so it remains to be seen if this will change Ukraine's strategy ... I tend to doubt it - they will have firepower to retaliate much harder, and at further distance, when they want to, but I expect they don't want to unilaterally escalate.