Is a Long War in Ukranian Territories Failable?

There's been a long war there since 20 14. The line of controlles has not been static int there've been since then. So i think it is possible that that could continue for some time to come. Tthe simply don't have a learning culture in the russian military, and therefore i can't see any huge breakthroughs in the near future. But say, very interested to hear doms take this idea around attrician rates,. whether russia, whether a long war in ukraine is actually feasible for the r Russian states.