Just to put things into perspective:
It took Russians almost a year and between 70,000 and 100,000 WIA / KIA in casualties to take 390 square kilometers (150 square miles) in the Avdiivka sector. They hailed this as a "genius" move.
Ukrainians took in 5 days more than 470 square kilometers (180 square miles) in Kursk, with no significant losses, according Russian claims even up to 700 square kilometers, and there is no sign of them stopping.