Everyone's aware the Russians are dug in. Mine fields and KA-52 choppers (which Russia is quickly running out of) are real threats.
This is why the counter offensive has been slow, but its also been methodical. Ukraine is picking and choosing its battles to minimize their own losses while maximizing Russian losses. Seriously, even though there's not much territory changing hands right now, the numbers paint a very vivid picture:
Visually confirmed Ukranian losses for 6/27 - 29 pieces of equipment
Visually confirmed Russian losses for 6/27 - 70 piece of equipment