The fronts are not moving. If any, Ukraine has made some minor advancements and Putin keeps sending unready troops to die for nothing. The number of artillery batteries sent now to Ukraine is starting to range in the hundreds, not to mention air defences and civil support. The tactical situation is looking grim for Putin.
The fronts are moving, just slowly. Russia moves at its own pace, using its strengths to compensate for its weaknesses. Ukraine has already carried out three waves of mobilization, while Russia has not carried out a single one. For Ukraine, this is a people's war, and Russia is conducting a special operation with the forces of the peacetime army. All military successes of Ukraine are either fictitious, or are connected with the navy, which it does not have itself, or are connected with Turkish drones. In the East, the positions of the Armed Forces of Ukraine are slowly being minced by artillery and Ukraine cannot do anything about this due to problems with logistics. Russian missiles disable railway electrical substations so that only diesel locomotives operate, this allows you to save infrastructure, but drastically reduce the amount of traffic on the railway.
Putin's army is unable to make any decisive advance. What you call grinding is in fact stagnating.
Decisive offensives mean great sacrifices, you confuse inability and unwillingness.