The Russians may very well be forced into falling back to pre-invasion fortified line in Luhansk over the next week (which is a very heavily fortified bunker/trench line) ~ basically the Donets River to the South, and the Russian border to the east... I don't think there is much in the way of any other fortified positions in the way, just the natural barrier of the Oskil river to cross which Ukraine already pretty much controls I believe.Standing question due to fog of war.....
How much of Luhansk Oblast is Ukraine able to claim before the Russian army can fortify and hold a defensive line?
Potential answers being.... Highway 66, the Donets River, Highway 21, .... the Russian Border?
Main risk of that advance is if Russia is able to organize their forces at Belgorod into a new re-invasion force, the north-east borders appear pretty porous. Plus that is a lot of area to try to cover from air strikes. Ukraine really should be hammering the mass-murder MLRS sites NE of Kharkiv in Russia, any Belgorod troop formations where Russia is trying to regroup for effectively a re-invasion, plus nearby Tomarovka military airbase ~ all which are certainly in HIMARS range ~ if the US isn't tying Ukraine's hands behind their back in fighting the war.