Russian forces are starting to seep into Sumy; probably they are trying to repeat what they did in Kharkiv and create a fixing operation in enemy territory and prevent them from crossing the border.
The Russians have Luhansk Oblast and their biggest final challenge in the war is the concentration of Donetsk Oblast cities. They are positioned outside of the fortified Pokrovsk line.
They are also starting to seep deeper into Z-Oblast. The final Kherson Bridgehead has not been attempted at all for ages.
The Russians will probably try to clear Donetsk first, and then concentrate on the Southern front after they are done. If they attempt to take the cities they have to systematically blow them up street by street like Bakhmut and Mariupol.