Liberate Slavyansk. If memory serves that is the first place in the Donbass, that the nazi militias attacked after the 2014 coup.
Very important to get those militias out of town quickly. You don’t want them hanging around!
I think you might see an advance in the south from Marinka (Vugledar is on the left flank) and a drive across steppe to Pokrovske. In the North you may see a drive across the Oskil and the retaking of Liman the Izium. With that, the Donbass becomes indefensible from a logistics perspective because the supply lines are all accross Steppe. The Donbass is industrialized and full of roads, hills, gullies and wooded areas.