Most likely they will be testing the waters to see what opposes them and to choose the tools to deal with any resistance based on the situation.
Pushing into enemy held territory is forcing them to send fresh meat to the front line to stop them... if they send too much then the best solution is air delivered HE power, but also starting something somewhere else on the line too.
Russia has the advantage and can bleed Kiev even faster with attacks in multiple areas... there does not need to be a hard set goal, the purpose is to force them to move their forces around the place which can be targeted and also to hit soft targets of moving troops and material and fuel and ammo which also needs to move with their soldiers for their soldiers to be effective.
The Russians are holding most of the cards and Kiev has nothing to play except shock attacks that have nothing but propaganda value which only children will be impressed by.
At the end of the day they will look at all the little painful attacks that Kiev inflicted on them and they will think about those when negotiating a peace agreement... essentially Kiev is delaying the inevitable and also making a cane for its own back... I can't see Russia allowing Kiev to retain access to the black sea... they are an ongoing threat to shipping and Russian commerce through that area...