Even if Russia is advancing 100 meters (300 feet) a day eventually it will reach the Western point of Ukraine unless something changes.
Of course, they are going slower than that. And also, at the current rate of attrition, Russia will run out of Russians long, long before that.
Something is changing every day as Russia's annual defence budget's worth of modern arms and training are deployed by Kyiv [1][2].
[1] https://www.cfr.org/article/how-much-aid-has-us-sent-ukraine...
This spring will show if they can change the current calculus but if not Russia is going to change the end game.